1QQ9

STREPTOMYCES GRISEUS AMINOPEPTIDASE COMPLEXED WITH METHIONINE

Summary for 1QQ9

• Entry DOI: 10.2210/pdb1qq9/pdb
• Related: 1CP7 1XJO
• Descriptor: AMINOPEPTIDASE, ZINC ION, CALCIUM ION, ... (5 entities in total)
• Functional Keywords: double-zinc metalloproteinaze, calcium activation, protein-inhibitor complex, hydrolase
• Biological source: Streptomyces griseus
• Cellular location: Secreted: P80561
• Total number of polymer chains: 1
• Total formula weight: 30070.76

Authors

Gilboa, R.,Greenblatt, H.M.,Perach, M.,Spungin-Bialik, A.,Lessel, U.,Schomburg, D.,Blumberg, S.,Shoham, G. (deposition date: 1999-06-12, release date: 2000-05-03, Last modification date: 2024-10-30)

Primary citation

Gilboa, R.,Greenblatt, H.M.,Perach, M.,Spungin-Bialik, A.,Lessel, U.,Wohlfahrt, G.,Schomburg, D.,Blumberg, S.,Shoham, G.
Interactions of Streptomyces griseus aminopeptidase with a methionine product analogue: a structural study at 1.53 A resolution.
Acta Crystallogr.,Sect.D, 56:551-558, 2000

PubMed Abstract: SGAP is an aminopeptidase present in the extracellular fluid of Streptomyces griseus cultures. It is a double-zinc enzyme with a strong preference for large hydrophobic amino-terminus residues. It is a monomeric (30 kDa) heat-stable enzyme, with a high and efficient catalytic activity modulated by calcium ions. The small size, high activity and heat stability make SGAP a very attractive enzyme for various biotechnological applications. Only one other related aminopeptidase (Aeromonas proteolytica AP; AAP) has been structurally analyzed to date and its structure was shown to be considerably similar to SGAP, despite the low sequence homology between the two enzymes. The motivation for the detailed structural analysis of SGAP originated from a strong mechanistic interest in the family of double-zinc aminopeptidases, combined with the high potential applicability of these enzymes. The 1.75 A crystallographic structure of native SGAP has been previously reported, but did not allow critical mechanistic interpretations owing to inconclusive structural regions around the active site. A more accurate structure of SGAP at 1.58 A resolution is reported in this paper, along with the 1.53 A resolution structure of the SGAP complex with inhibitory methionine, which is also a product of the SGAP catalytic process. These two high-resolution structures enable a better understanding of the SGAP binding mode of both substrates and products. These studies allowed the tracing of the previously disordered region of the enzyme (Glu196-Arg202) and the identification of some of the functional groups of the enzyme that are involved in enzyme-substrate interactions (Asp160, Met161, Gly201, Arg202 and Phe219). These studies also suggest that Glu131 is directly involved in the catalytic mechanism of SGAP, probably as the hydrolytic nucleophile. The structural results are compared with a recent structure of AAP with an hydroxamate inhibitor in order to draw general functional conclusions which are relevant for this family of low molecular-weight aminopeptidases.

PubMed: 10771423
DOI: 10.1107/S0907444900002420

Experimental method

X-RAY DIFFRACTION (1.53 Å)