universal stress protein At3g01520 and similar proteins
This subfamily includes plant and fungal proteins of unknown function, including Arabidopsis thaliana At3g01520. A. thaliana contains 44 USP domain-containing proteins; the USP domain is found either in a small protein with unknown physiological function or as an N-terminal portion of a multi-domain protein, usually a protein kinase. The gene At3g01520 of Arabidopsis thaliana encodes a 175-residue universal stress protein (USP)-like protein which is widely found in the genomes of bacteria, as well as fungi, protozoa, and plants. The bound AMP and conservation of residues in the ATP-binding loop suggest that the protein At3g01520 belongs to the ATP-binding USP subfamily. Universal stress proteins (USPs) are small cytoplasmic bacterial proteins whose expression is enhanced when the cell is exposed to stress agents. USP enhances the rate of cell survival during prolonged exposure to such conditions, and may provide a general "stress endurance" activity.
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