DIRS1 family of RNase HI in long-term repeat retroelements; Ribonuclease H (RNase H) enzymes are divided into two major families, Type 1 and Type 2, based on amino acid sequence similarities and biochemical properties. RNase H is an endonuclease that cleaves the RNA strand of an RNA/DNA hybrid in a sequence non-specific manner in the presence of divalent cations. RNase H is widely present in various organisms, including bacteria, archaea and eukaryotes. RNase HI has also been observed as adjunct domains to the reverse transcriptase gene in retroviruses, in long-term repeat (LTR)-bearing retrotransposons and non-LTR retrotransposons. RNase HI in LTR retrotransposons perform degradation of the original RNA template, generation of a polypurine tract (the primer for plus-strand DNA synthesis), and final removal of RNA primers from newly synthesized minus and plus strands. The catalytic residues for RNase H enzymatic activity, three aspartatic acids and one glutamic acid residue (DEDD), are unvaried across all RNase H domains. Phylogenetic patterns of RNase HI of LTR retroelements is classified into five major families, Ty3/Gypsy, Ty1/Copia, Bel/Pao, DIRS1 and the vertebrate retroviruses. The structural features of DIRS1-group elements are different from typical LTR elements. RNase H inhibitors have been explored as an anti-HIV drug target because RNase H inactivation inhibits reverse transcription.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1815480888   2 FSDASLTGWGAYCNNERANGYWTIDDKNKHINFLELKAAYFGLQCFAKTLKDCNILLRIDNTTAIAYLNKMGGAQHTHLN 81
Cdd:cd09275     3 FTDASLSGWGAYLLNSRAHGPWSADERNKHINLLELKAVLLALQHFAAELKNRKILIRTDNTTAVAYINKQGGTSSPPLL 82

                          90       100       110
                  ....*....|....*....|....*....|....*.
gi 1815480888  82 DITRKIWQWCERRNIVIFASYIASKENVEADEESRR 117
Cdd:cd09275    83 ALARQILLWCEQRNIWLRASHIPGVLNTEADRLSRL 118

DIRS1 family of RNase HI in long-term repeat retroelements; Ribonuclease H (RNase H) enzymes are divided into two major families, Type 1 and Type 2, based on amino acid sequence similarities and biochemical properties. RNase H is an endonuclease that cleaves the RNA strand of an RNA/DNA hybrid in a sequence non-specific manner in the presence of divalent cations. RNase H is widely present in various organisms, including bacteria, archaea and eukaryotes. RNase HI has also been observed as adjunct domains to the reverse transcriptase gene in retroviruses, in long-term repeat (LTR)-bearing retrotransposons and non-LTR retrotransposons. RNase HI in LTR retrotransposons perform degradation of the original RNA template, generation of a polypurine tract (the primer for plus-strand DNA synthesis), and final removal of RNA primers from newly synthesized minus and plus strands. The catalytic residues for RNase H enzymatic activity, three aspartatic acids and one glutamic acid residue (DEDD), are unvaried across all RNase H domains. Phylogenetic patterns of RNase HI of LTR retroelements is classified into five major families, Ty3/Gypsy, Ty1/Copia, Bel/Pao, DIRS1 and the vertebrate retroviruses. The structural features of DIRS1-group elements are different from typical LTR elements. RNase H inhibitors have been explored as an anti-HIV drug target because RNase H inactivation inhibits reverse transcription.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1815480888   2 FSDASLTGWGAYCNNERANGYWTIDDKNKHINFLELKAAYFGLQCFAKTLKDCNILLRIDNTTAIAYLNKMGGAQHTHLN 81
Cdd:cd09275     3 FTDASLSGWGAYLLNSRAHGPWSADERNKHINLLELKAVLLALQHFAAELKNRKILIRTDNTTAVAYINKQGGTSSPPLL 82

                          90       100       110
                  ....*....|....*....|....*....|....*.
gi 1815480888  82 DITRKIWQWCERRNIVIFASYIASKENVEADEESRR 117
Cdd:cd09275    83 ALARQILLWCEQRNIWLRASHIPGVLNTEADRLSRL 118

DIRS1 family of RNase HI in long-term repeat retroelements; Ribonuclease H (RNase H) enzymes are divided into two major families, Type 1 and Type 2, based on amino acid sequence similarities and biochemical properties. RNase H is an endonuclease that cleaves the RNA strand of an RNA/DNA hybrid in a sequence non-specific manner in the presence of divalent cations. RNase H is widely present in various organisms, including bacteria, archaea and eukaryotes. RNase HI has also been observed as adjunct domains to the reverse transcriptase gene in retroviruses, in long-term repeat (LTR)-bearing retrotransposons and non-LTR retrotransposons. RNase HI in LTR retrotransposons perform degradation of the original RNA template, generation of a polypurine tract (the primer for plus-strand DNA synthesis), and final removal of RNA primers from newly synthesized minus and plus strands. The catalytic residues for RNase H enzymatic activity, three aspartatic acids and one glutamic acid residue (DEDD), are unvaried across all RNase H domains. Phylogenetic patterns of RNase HI of LTR retroelements is classified into five major families, Ty3/Gypsy, Ty1/Copia, Bel/Pao, DIRS1 and the vertebrate retroviruses. The structural features of DIRS1-group elements are different from typical LTR elements. RNase H inhibitors have been explored as an anti-HIV drug target because RNase H inactivation inhibits reverse transcription.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1815480888   2 FSDASLTGWGAYCNNERANGYWTIDDKNKHINFLELKAAYFGLQCFAKTLKDCNILLRIDNTTAIAYLNKMGGAQHTHLN 81
Cdd:cd09275     3 FTDASLSGWGAYLLNSRAHGPWSADERNKHINLLELKAVLLALQHFAAELKNRKILIRTDNTTAVAYINKQGGTSSPPLL 82

                          90       100       110
                  ....*....|....*....|....*....|....*.
gi 1815480888  82 DITRKIWQWCERRNIVIFASYIASKENVEADEESRR 117
Cdd:cd09275    83 ALARQILLWCEQRNIWLRASHIPGVLNTEADRLSRL 118