3gcb | pdb_00003gcb
GAL6 (YEAST BLEOMYCIN HYDROLASE) MUTANT C73A/DELTAK454
Structural highlights
FunctionBLH1_YEAST The normal physiological role of the enzyme is unknown, but it is not essential for the viability of yeast cells. Has aminopeptidase activity, shortening substrate peptides sequentially by 1 amino acid. Has bleomycin hydrolase activity, which can protect the cell from the toxic effects of bleomycin. Has homocysteine-thiolactonase activity, protecting the cell against homocysteine toxicity. Acts as a repressor in the GAL4 regulatory system, but this does not require either the peptidase or nucleic acid-binding activities.[1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe Gal6 protease is in a class of cysteine peptidases identified by their ability to inactivate the anti-cancer drug bleomycin. The protein forms a barrel structure with the active sites embedded in a channel as in the proteasome. In Gal6 the C termini lie in the active site clefts. We show that Gal6 acts as a carboxypeptidase on its C terminus to convert itself to an aminopeptidase and peptide ligase. The substrate specificity of the peptidase activity is determined by the position of the C terminus of Gal6 rather than the sequence of the substrate. We propose a model to explain these diverse activities and Gal6's singular ability to inactivate bleomycin. The unusual active site of Gal6/bleomycin hydrolase can act as a carboxypeptidase, aminopeptidase, and peptide ligase.,Zheng W, Johnston SA, Joshua-Tor L Cell. 1998 Apr 3;93(1):103-9. PMID:9546396[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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