beta-ketoacyl reductase (KR) domain of fatty acid synthase (FAS), subgroup 1, complex (x) SDRs; NADP-dependent KR domain of the multidomain type I FAS, a complex SDR family. This subfamily also includes proteins identified as polyketide synthase (PKS), a protein with related modular protein architecture and similar function. It includes the KR domains of mammalian and chicken FAS, and Dictyostelium discoideum putative polyketide synthases (PKSs). These KR domains contain two subdomains, each of which is related to SDR Rossmann fold domains. However, while the C-terminal subdomain has an active site similar to the other SDRs and a NADP-binding capability, the N-terminal SDR-like subdomain is truncated and lacks these functions, serving a supportive structural role. In some instances, such as porcine FAS, an enoyl reductase (a Rossman fold NAD-binding domain of the medium-chain dehydrogenase/reductase, MDR family) module is inserted between the sub-domains. Fatty acid synthesis occurs via the stepwise elongation of a chain (which is attached to acyl carrier protein, ACP) with 2-carbon units. Eukaryotic systems consists of large, multifunctional synthases (type I) while bacterial, type II systems, use single function proteins. Fungal fatty acid synthesis uses a dodecamer of 6 alpha and 6 beta subunits. In mammalian type FAS cycles, ketoacyl synthase forms acetoacetyl-ACP which is reduced by the NADP-dependent beta-ketoacyl reductase (KR), forming beta-hydroxyacyl-ACP, which is in turn dehydrated by dehydratase to a beta-enoyl intermediate, which is reduced by NADP-dependent beta-enoyl reductase (ER); this KR and ER are members of the SDR family. This KR subfamily has an active site tetrad with a similar 3D orientation compared to archetypical SDRs, but the active site Lys and Asn residue positions are swapped. The characteristic NADP-binding is typical of the multidomain complex SDRs, with a GGXGXXG NADP binding motif. SDRs are a functionally diverse family of oxidoreductases that have a single domain with a structurally conserved Rossmann fold (alpha/beta folding pattern with a central beta-sheet), an NAD(P)(H)-binding region, and a structurally diverse C-terminal region. Classical SDRs are typically about 250 residues long, while extended SDRs are approximately 350 residues. Sequence identity between different SDR enzymes are typically in the 15-30% range, but the enzymes share the Rossmann fold NAD-binding motif and characteristic NAD-binding and catalytic sequence patterns. These enzymes catalyze a wide range of activities including the metabolism of steroids, cofactors, carbohydrates, lipids, aromatic compounds, and amino acids, and act in redox sensing. Classical SDRs have an TGXXX[AG]XG cofactor binding motif and a YXXXK active site motif, with the Tyr residue of the active site motif serving as a critical catalytic residue (Tyr-151, human prostaglandin dehydrogenase (PGDH) numbering). In addition to the Tyr and Lys, there is often an upstream Ser (Ser-138, PGDH numbering) and/or an Asn (Asn-107, PGDH numbering) contributing to the active site; while substrate binding is in the C-terminal region, which determines specificity. The standard reaction mechanism is a 4-pro-S hydride transfer and proton relay involving the conserved Tyr and Lys, a water molecule stabilized by Asn, and nicotinamide. Extended SDRs have additional elements in the C-terminal region, and typically have a TGXXGXXG cofactor binding motif. Complex (multidomain) SDRs such as ketoreductase domains of fatty acid synthase have a GGXGXXG NAD(P)-binding motif and an altered active site motif (YXXXN). Fungal type KRs have a TGXXXGX(1-2)G NAD(P)-binding motif. Some atypical SDRs have lost catalytic activity and/or have an unusual NAD(P)-binding motif and missing or unusual active site residues. Reactions catalyzed within the SDR family include isomerization, decarboxylation, epimerization, C=N bond reduction, dehydratase activity, dehalogenation, Enoyl-CoA reduction, and carbonyl-alcohol oxidoreduction.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 332032403  24 WLIIRGAR-NIVLISRNGIKNGYQRMkIRLWKSYGVNVlIIKNIDVADLKDCEYI---LRTAEKEAPVDAIFNLGVVLKD 99
Cdd:cd08954  237 WLVKRGAVeNIIILSRSGMKWELELL-IREWKSQNIKF-HFVSVDVSDVSSLEKAinlILNAPKIGPIGGIFHLAFVLID 314

                         90       100       110       120       130
                 ....*....|....*....|....*....|....*....|....*....|.
gi 332032403 100 DIFKNQTAESFAESFQSKARATQMLDKLSRKICLNLRHFVVFSSVSCGRGN 150
Cdd:cd08954  315 KVLEIDTESLFISVNKAKVMGAINLHNQSIKRCWKLDYFVLFSSVSSIRGS 365

beta-ketoacyl reductase (KR) domain of fatty acid synthase (FAS), subgroup 1, complex (x) SDRs; NADP-dependent KR domain of the multidomain type I FAS, a complex SDR family. This subfamily also includes proteins identified as polyketide synthase (PKS), a protein with related modular protein architecture and similar function. It includes the KR domains of mammalian and chicken FAS, and Dictyostelium discoideum putative polyketide synthases (PKSs). These KR domains contain two subdomains, each of which is related to SDR Rossmann fold domains. However, while the C-terminal subdomain has an active site similar to the other SDRs and a NADP-binding capability, the N-terminal SDR-like subdomain is truncated and lacks these functions, serving a supportive structural role. In some instances, such as porcine FAS, an enoyl reductase (a Rossman fold NAD-binding domain of the medium-chain dehydrogenase/reductase, MDR family) module is inserted between the sub-domains. Fatty acid synthesis occurs via the stepwise elongation of a chain (which is attached to acyl carrier protein, ACP) with 2-carbon units. Eukaryotic systems consists of large, multifunctional synthases (type I) while bacterial, type II systems, use single function proteins. Fungal fatty acid synthesis uses a dodecamer of 6 alpha and 6 beta subunits. In mammalian type FAS cycles, ketoacyl synthase forms acetoacetyl-ACP which is reduced by the NADP-dependent beta-ketoacyl reductase (KR), forming beta-hydroxyacyl-ACP, which is in turn dehydrated by dehydratase to a beta-enoyl intermediate, which is reduced by NADP-dependent beta-enoyl reductase (ER); this KR and ER are members of the SDR family. This KR subfamily has an active site tetrad with a similar 3D orientation compared to archetypical SDRs, but the active site Lys and Asn residue positions are swapped. The characteristic NADP-binding is typical of the multidomain complex SDRs, with a GGXGXXG NADP binding motif. SDRs are a functionally diverse family of oxidoreductases that have a single domain with a structurally conserved Rossmann fold (alpha/beta folding pattern with a central beta-sheet), an NAD(P)(H)-binding region, and a structurally diverse C-terminal region. Classical SDRs are typically about 250 residues long, while extended SDRs are approximately 350 residues. Sequence identity between different SDR enzymes are typically in the 15-30% range, but the enzymes share the Rossmann fold NAD-binding motif and characteristic NAD-binding and catalytic sequence patterns. These enzymes catalyze a wide range of activities including the metabolism of steroids, cofactors, carbohydrates, lipids, aromatic compounds, and amino acids, and act in redox sensing. Classical SDRs have an TGXXX[AG]XG cofactor binding motif and a YXXXK active site motif, with the Tyr residue of the active site motif serving as a critical catalytic residue (Tyr-151, human prostaglandin dehydrogenase (PGDH) numbering). In addition to the Tyr and Lys, there is often an upstream Ser (Ser-138, PGDH numbering) and/or an Asn (Asn-107, PGDH numbering) contributing to the active site; while substrate binding is in the C-terminal region, which determines specificity. The standard reaction mechanism is a 4-pro-S hydride transfer and proton relay involving the conserved Tyr and Lys, a water molecule stabilized by Asn, and nicotinamide. Extended SDRs have additional elements in the C-terminal region, and typically have a TGXXGXXG cofactor binding motif. Complex (multidomain) SDRs such as ketoreductase domains of fatty acid synthase have a GGXGXXG NAD(P)-binding motif and an altered active site motif (YXXXN). Fungal type KRs have a TGXXXGX(1-2)G NAD(P)-binding motif. Some atypical SDRs have lost catalytic activity and/or have an unusual NAD(P)-binding motif and missing or unusual active site residues. Reactions catalyzed within the SDR family include isomerization, decarboxylation, epimerization, C=N bond reduction, dehydratase activity, dehalogenation, Enoyl-CoA reduction, and carbonyl-alcohol oxidoreduction.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 332032403  24 WLIIRGAR-NIVLISRNGIKNGYQRMkIRLWKSYGVNVlIIKNIDVADLKDCEYI---LRTAEKEAPVDAIFNLGVVLKD 99
Cdd:cd08954  237 WLVKRGAVeNIIILSRSGMKWELELL-IREWKSQNIKF-HFVSVDVSDVSSLEKAinlILNAPKIGPIGGIFHLAFVLID 314

                         90       100       110       120       130
                 ....*....|....*....|....*....|....*....|....*....|.
gi 332032403 100 DIFKNQTAESFAESFQSKARATQMLDKLSRKICLNLRHFVVFSSVSCGRGN 150
Cdd:cd08954  315 KVLEIDTESLFISVNKAKVMGAINLHNQSIKRCWKLDYFVLFSSVSSIRGS 365

ketoreductase (KR) and fatty acid synthase (FAS), complex (x) SDRs; Ketoreductase, a module of the multidomain polyketide synthase (PKS), has 2 subdomains, each corresponding to a SDR family monomer. The C-terminal subdomain catalyzes the NADPH-dependent reduction of the beta-carbonyl of a polyketide to a hydroxyl group, a step in the biosynthesis of polyketides, such as erythromycin. The N-terminal subdomain, an interdomain linker, is a truncated Rossmann fold which acts to stabilizes the catalytic subdomain. Unlike typical SDRs, the isolated domain does not oligomerize but is composed of 2 subdomains, each resembling an SDR monomer. The active site resembles that of typical SDRs, except that the usual positions of the catalytic Asn and Tyr are swapped, so that the canonical YXXXK motif changes to YXXXN. Modular PKSs are multifunctional structures in which the makeup recapitulates that found in (and may have evolved from) FAS. In some instances, such as porcine FAS, an enoyl reductase (ER) module is inserted between the sub-domains. Fatty acid synthesis occurs via the stepwise elongation of a chain (which is attached to acyl carrier protein, ACP) with 2-carbon units. Eukaryotic systems consist of large, multifunctional synthases (type I) while bacterial, type II systems, use single function proteins. Fungal fatty acid synthase uses a dodecamer of 6 alpha and 6 beta subunits. In mammalian type FAS cycles, ketoacyl synthase forms acetoacetyl-ACP which is reduced by the NADP-dependent beta-KR, forming beta-hydroxyacyl-ACP, which is in turn dehydrated by dehydratase to a beta-enoyl intermediate, which is reduced by NADP-dependent beta-ER. Polyketide synthesis also proceeds via the addition of 2-carbon units as in fatty acid synthesis. The complex SDR NADP-binding motif, GGXGXXG, is often present, but is not strictly conserved in each instance of the module. SDRs are a functionally diverse family of oxidoreductases that have a single domain with a structurally conserved Rossmann fold (alpha/beta folding pattern with a central beta-sheet), an NAD(P)(H)-binding region, and a structurally diverse C-terminal region. Classical SDRs are typically about 250 residues long, while extended SDRs are approximately 350 residues. Sequence identity between different SDR enzymes are typically in the 15-30% range, but the enzymes share the Rossmann fold NAD-binding motif and characteristic NAD-binding and catalytic sequence patterns. These enzymes catalyze a wide range of activities including the metabolism of steroids, cofactors, carbohydrates, lipids, aromatic compounds, and amino acids, and act in redox sensing. Classical SDRs have an TGXXX[AG]XG cofactor binding motif and a YXXXK active site motif, with the Tyr residue of the active site motif serving as a critical catalytic residue (Tyr-151, human prostaglandin dehydrogenase (PGDH) numbering). In addition to the Tyr and Lys, there is often an upstream Ser (Ser-138, PGDH numbering) and/or an Asn (Asn-107, PGDH numbering) contributing to the active site; while substrate binding is in the C-terminal region, which determines specificity. The standard reaction mechanism is a 4-pro-S hydride transfer and proton relay involving the conserved Tyr and Lys, a water molecule stabilized by Asn, and nicotinamide. Extended SDRs have additional elements in the C-terminal region, and typically have a TGXXGXXG cofactor binding motif. Complex (multidomain) SDRs such as ketoreductase domains of fatty acid synthase have a GGXGXXG NAD(P)-binding motif and an altered active site motif (YXXXN). Fungal type KRs have a TGXXXGX(1-2)G NAD(P)-binding motif. Some atypical SDRs have lost catalytic activity and/or have an unusual NAD(P)-binding motif and missing or unusual active site residues. Reactions catalyzed within the SDR family include isomerization, decarboxylation, epimerization, C=N bond reduction, dehydratase activity, dehalogenation, Enoyl-CoA reduction, and carbonyl-alcohol oxidoreduction.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 332032403  22 TDWLIIRGARNIVLISRNGIKNGYQRMkIRLWKSYGVNVLIIkNIDVADLKDCEYILRTAEKEAPVDAIFNLGVVLKDDI 101
Cdd:cd05274  167 ARWLAARGARHLVLLSRRGPAPRAAAR-AALLRAGGARVSVV-RCDVTDPAALAALLAELAAGGPLAGVIHAAGVLRDAL 244

                         90       100       110       120
                 ....*....|....*....|....*....|....*....|....*....
gi 332032403 102 FKNQTAESFAESFQSKARATQMLDKLSRKicLNLRHFVVFSSVSCGRGN 150
Cdd:cd05274  245 LAELTPAAFAAVLAAKVAGALNLHELTPD--LPLDFFVLFSSVAALLGG 291

beta-ketoacyl reductase (KR) domain of fatty acid synthase (FAS), subgroup 3, complex (x); Ketoreductase, a module of the multidomain polyketide synthase (PKS), has 2 subdomains, each corresponding to a SDR family monomer. The C-terminal subdomain catalyzes the NADPH-dependent reduction of the beta-carbonyl of a polyketide to a hydroxyl group, a step in the biosynthesis of polyketides, such as erythromycin. The N-terminal subdomain, an interdomain linker, is a truncated Rossmann fold which acts to stabilizes the catalytic subdomain. Unlike typical SDRs, the isolated domain does not oligomerize but is composed of 2 subdomains, each resembling an SDR monomer. The active site resembles that of typical SDRs, except that the usual positions of the catalytic Asn and Tyr are swapped, so that the canonical YXXXK motif changes to YXXXN. Modular PKSs are multifunctional structures in which the makeup recapitulates that found in (and may have evolved from) FAS. In some instances, such as porcine FAS, an enoyl reductase (ER) module is inserted between the sub-domains. Fatty acid synthesis occurs via the stepwise elongation of a chain (which is attached to acyl carrier protein, ACP) with 2-carbon units. Eukaryotic systems consists of large, multifunctional synthases (type I) while bacterial, type II systems, use single function proteins. Fungal fatty acid synthesis uses a dodecamer of 6 alpha and 6 beta subunits. In mammalian type FAS cycles, ketoacyl synthase forms acetoacetyl-ACP which is reduced by the NADP-dependent beta-KR, forming beta-hydroxyacyl-ACP, which is in turn dehydrated by dehydratase to a beta-enoyl intermediate, which is reduced by NADP-dependent beta- ER. Polyketide synthesis also proceeds via the addition of 2-carbon units as in fatty acid synthesis. The complex SDR NADP-binding motif, GGXGXXG, is often present, but is not strictly conserved in each instance of the module. This subfamily includes KR domains found in many multidomain PKSs, including six of seven Sorangium cellulosum PKSs (encoded by spiDEFGHIJ) which participate in the synthesis of the polyketide scaffold of the cytotoxic spiroketal polyketide spirangien. These seven PKSs have either a single PKS module (SpiF), two PKR modules (SpiD,-E,-I,-J), or three PKS modules (SpiG,-H). This subfamily includes the second KR domains of SpiE,-G, I, and -J, both KR domains of SpiD, and the third KR domain of SpiH. The single KR domain of SpiF, the first and second KR domains of SpiH, the first KR domains of SpiE,-G,- I, and -J, and the third KR domain of SpiG, belong to a different KR_FAS_SDR subfamily. SDRs are a functionally diverse family of oxidoreductases that have a single domain with a structurally conserved Rossmann fold (alpha/beta folding pattern with a central beta-sheet), an NAD(P)(H)-binding region, and a structurally diverse C-terminal region. Classical SDRs are typically about 250 residues long, while extended SDRs are approximately 350 residues. Sequence identity between different SDR enzymes are typically in the 15-30% range, but the enzymes share the Rossmann fold NAD-binding motif and characteristic NAD-binding and catalytic sequence patterns. These enzymes catalyze a wide range of activities including the metabolism of steroids, cofactors, carbohydrates, lipids, aromatic compounds, and amino acids, and act in redox sensing. Classical SDRs have an TGXXX[AG]XG cofactor binding motif and a YXXXK active site motif, with the Tyr residue of the active site motif serving as a critical catalytic residue (Tyr-151, human prostaglandin dehydrogenase (PGDH) numbering). In addition to the Tyr and Lys, there is often an upstream Ser (Ser-138, PGDH numbering) and/or an Asn (Asn-107, PGDH numbering) contributing to the active site; while substrate binding is in the C-terminal region, which determines specificity. The standard reaction mechanism is a 4-pro-S hydride transfer and proton relay involving the conserved Tyr and Lys, a water molecule stabilized by Asn, and nicotinamide. Extended SDRs have additional elements in the C-terminal region, and typically have a TGXXGXXG cofactor binding motif. Complex (multidomain) SDRs such as ketoreductase domains of fatty acid synthase have a GGXGXXG NAD(P)-binding motif and an altered active site motif (YXXXN). Fungal type KRs have a TGXXXGX(1-2)G NAD(P)-binding motif. Some atypical SDRs have lost catalytic activity and/or have an unusual NAD(P)-binding motif and missing or unusual active site residues. Reactions catalyzed within the SDR family include isomerization, decarboxylation, epimerization, C=N bond reduction, dehydratase activity, dehalogenation, Enoyl-CoA reduction, and carbonyl-alcohol oxidoreduction.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 332032403  28 RGARNIVLISRNG-IKNGYQRMKIRLwKSYGVNVLIIKnIDVADLKDCEYILRTAEKEAPVDAIFNLGVVLKDDIFKNQT 106
Cdd:cd08956  217 HGVRHLLLVSRRGpDAPGAAELVAEL-AALGAEVTVAA-CDVADRAALAALLAAVPADHPLTAVVHAAGVLDDGVLTSLT 294

                         90       100       110
                 ....*....|....*....|....*....|....*....
gi 332032403 107 AESFAESFQSKARATQMLDKLSRKicLNLRHFVVFSSVS 145
Cdd:cd08956  295 PERLDAVLRPKVDAAWHLHELTRD--LDLAAFVLFSSAA 331

ketoreductase (KR), subgroup 1, complex (x) SDRs; Ketoreductase, a module of the multidomain polyketide synthase (PKS), has 2 subdomains, each corresponding to a SDR family monomer. The C-terminal subdomain catalyzes the NADPH-dependent reduction of the beta-carbonyl of a polyketide to a hydroxyl group, a step in the biosynthesis of polyketides, such as erythromycin. The N-terminal subdomain, an interdomain linker, is a truncated Rossmann fold which acts to stabilizes the catalytic subdomain. Unlike typical SDRs, the isolated domain does not oligomerize but is composed of 2 subdomains, each resembling an SDR monomer. The active site resembles that of typical SDRs, except that the usual positions of the catalytic Asn and Tyr are swapped, so that the canonical YXXXK motif changes to YXXXN. Modular PKSs are multifunctional structures in which the makeup recapitulates that found in (and may have evolved from) FAS. Polyketide synthesis also proceeds via the addition of 2-carbon units as in fatty acid synthesis. The complex SDR NADP-binding motif, GGXGXXG, is often present, but is not strictly conserved in each instance of the module. This subfamily includes KR domains found in many multidomain PKSs, including six of seven Sorangium cellulosum PKSs (encoded by spiDEFGHIJ) which participate in the synthesis of the polyketide scaffold of the cytotoxic spiroketal polyketide spirangien. These seven PKSs have either a single PKS module (SpiF), two PKR modules (SpiD,-E,-I,-J), or three PKS modules (SpiG,-H). This subfamily includes the single KR domain of SpiF, the first KR domains of SpiE,-G,H,-I,and #J, the third KR domain of SpiG, and the second KR domain of SpiH. The second KR domains of SpiE,-G, I, and #J, and the KR domains of SpiD, belong to a different KR_FAS_SDR subfamily. SDRs are a functionally diverse family of oxidoreductases that have a single domain with a structurally conserved Rossmann fold (alpha/beta folding pattern with a central beta-sheet), an NAD(P)(H)-binding region, and a structurally diverse C-terminal region. Classical SDRs are typically about 250 residues long, while extended SDRs are approximately 350 residues. Sequence identity between different SDR enzymes are typically in the 15-30% range, but the enzymes share the Rossmann fold NAD-binding motif and characteristic NAD-binding and catalytic sequence patterns. These enzymes catalyze a wide range of activities including the metabolism of steroids, cofactors, carbohydrates, lipids, aromatic compounds, and amino acids, and act in redox sensing. Classical SDRs have an TGXXX[AG]XG cofactor binding motif and a YXXXK active site motif, with the Tyr residue of the active site motif serving as a critical catalytic residue (Tyr-151, human prostaglandin dehydrogenase (PGDH) numbering). In addition to the Tyr and Lys, there is often an upstream Ser (Ser-138, PGDH numbering) and/or an Asn (Asn-107, PGDH numbering) contributing to the active site; while substrate binding is in the C-terminal region, which determines specificity. The standard reaction mechanism is a 4-pro-S hydride transfer and proton relay involving the conserved Tyr and Lys, a water molecule stabilized by Asn, and nicotinamide. Extended SDRs have additional elements in the C-terminal region, and typically have a TGXXGXXG cofactor binding motif. Complex (multidomain) SDRs such as ketoreductase domains of fatty acid synthase have a GGXGXXG NAD(P)-binding motif and an altered active site motif (YXXXN). Fungal type KRs have a TGXXXGX(1-2)G NAD(P)-binding motif. Some atypical SDRs have lost catalytic activity and/or have an unusual NAD(P)-binding motif and missing or unusual active site residues. Reactions catalyzed within the SDR family include isomerization, decarboxylation, epimerization, C=N bond reduction, dehydratase activity, dehalogenation, Enoyl-CoA reduction, and carbonyl-alcohol oxidoreduction.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 332032403  24 WLIIRGARNIVLISRNGIKNGYQRMKIRLWKSYGVNVLIIKnIDVADLKDCEYILRTAEKEAPVDAIFNLGVVLKDDIFK 103
Cdd:cd08952  249 WLARRGAEHLVLTSRRGPDAPGAAELVAELTALGARVTVAA-CDVADRDALAALLAALPAGHPLTAVVHAAGVLDDGPLD 327

                         90       100       110       120
                 ....*....|....*....|....*....|....*....|..
gi 332032403 104 NQTAESFAESFQSKARATQMLDKLSRKicLNLRHFVVFSSVS 145
Cdd:cd08952  328 DLTPERLAEVLRAKVAGARHLDELTRD--RDLDAFVLFSSIA 367