Structural highlights
Function
[BLH1_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 PubMed
The 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
- ↑ Wang H, Ramotar D. Cellular resistance to bleomycin in Saccharomyces cerevisiae is not affected by changes in bleomycin hydrolase levels. Biochem Cell Biol. 2002;80(6):789-96. PMID:12555812
- ↑ Zimny J, Sikora M, Guranowski A, Jakubowski H. Protective mechanisms against homocysteine toxicity: the role of bleomycin hydrolase. J Biol Chem. 2006 Aug 11;281(32):22485-92. Epub 2006 Jun 12. PMID:16769724 doi:http://dx.doi.org/M603656200
- ↑ Zheng W, Johnston SA, Joshua-Tor L. The unusual active site of Gal6/bleomycin hydrolase can act as a carboxypeptidase, aminopeptidase, and peptide ligase. Cell. 1998 Apr 3;93(1):103-9. PMID:9546396
