Naslov
Yeast Ortholog of Peptidase Family M49 : the Role of Invariant Glu461 and Tyr327

Autori
Jajčanin Jozić, Nina ; Macheroux, Peter ; Abramić, Marija

Izvornik
Croatica chemica acta (0011-1643) 85 (2012), 4; 535-540

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
enzyme catalysis ; metallopeptidase ; protein structure-function ; site-directed mutagenesis ; yeast Saccharomyces cerevisiae

Sažetak
Metallopeptidase family M49 is characterized by five conserved sequence regions and the unique motif HEXXGH with two histidines - ligands of the active-site zinc ion. The crystal structure of the yeast ortholog represents a prototype for the whole family. To investigate the role of two invariant amino acid residues, a Glu461 of the zinc-binding motif, and a Tyr327, 21Å from the catalytic zinc center, mutational analysis of the yeast enzyme was performed. The substitution of Glu461 to glutamine decreased kcat for the substrate hydrolysis almost by 10 000-fold. The replacement of Tyr327 by Phe or Ala reduced the catalytic efficiency (kcat/Km) by two orders of magnitude. The affinity for the heptapeptide valorphin was siginificantly lowered in all mutants, in-dicating the contribution of both Glu461 and Tyr327 in substrate binding. Taken together, the effect of mutating Glu461 is consistent with this residue being essential in M49 peptidase catalysis.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

POVEZANOST RADA