The crystal structure of Leishmania major 3-mercaptopyruvate sulfurtransferase. A three-domain architecture with a serine protease-like triad at the active site.
Leishmania major 3-mercaptopyruvate sulfurtransferase is a crescent-shaped molecule comprising three domains. The N-terminal and central domains are similar to the thiosulfate sulfurtransferase rhodanese and create the active site containing a persulfurated catalytic cysteine (Cys-253) and an inhibitory sulfite coordinated by Arg-74 and Arg-185. A serine protease-like triad, comprising Asp-61, His-75, and Ser-255, is near Cys-253 and represents a conserved feature that distinguishes 3-mercaptopyruvate sulfurtransferases from thiosulfate sulfurtransferases. During catalysis, Ser-255 may polarize the carbonyl group of 3-mercaptopyruvate to assist thiophilic attack, whereas Arg-74 and Arg-185 bind the carboxylate group. The enzyme hydrolyzes benzoyl-Arg-p-nitroanilide, an activity that is sensitive to the presence of the serine protease inhibitor N alpha-p-tosyl-L-lysine chloromethyl ketone, which also lowers 3-mercaptopyruvate sulfurtransferase activity, presumably by interference with the contribution of Ser-255. The L. major 3-mercaptopyruvate sulfurtransferase is unusual with an 80-amino acid C-terminal domain, bearing remarkable structural similarity to the FK506-binding protein class of peptidylprolyl cis/trans-isomerase. This domain may be involved in mediating protein folding and sulfurtransferase-protein interactions.
Alphey
Magnus S
MS
Division of Biological Chemistry and Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom.
Williams
Roderick A M
RA
Mottram
Jeremy C
JC
Coombs
Graham H
GH
Hunter
William N
WN
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002384:Catalysis; D020134:Catalytic Domain; D002417:Cattle; D018360:Crystallography, X-Ray; D003545:Cysteine / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D006868:Hydrolysis; D007166:Immunosuppressive Agents / Q000494:pharmacology; D018320:Leishmania major / Q000201:enzymology*; D008956:Models, Chemical; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012697:Serine Endopeptidases / Q000737:chemistry; D013466:Sulfurtransferases / Q000737:chemistry*; D016559:Tacrolimus / Q000737:chemistry; D013884:Thiosulfate Sulfurtransferase / Q000737:chemistry
D007166:Immunosuppressive Agents; D013466:Sulfurtransferases; D013884:Thiosulfate Sulfurtransferase; C021550:3-mercaptopyruvate sulphurtransferase; D012697:Serine Endopeptidases; D003545:Cysteine; D016559:Tacrolimus