1SGC

THE 1.8 ANGSTROMS STRUCTURE OF THE COMPLEX BETWEEN CHYMOSTATIN AND STREPTOMYCES GRISEUS PROTEASE A. A MODEL FOR SERINE PROTEASE CATALYTIC TETRAHEDRAL INTERMEDIATES

Summary for 1SGC

• Entry DOI: 10.2210/pdb1sgc/pdb
• Related PRD ID: PRD_000558
• Descriptor: PROTEINASE A, CHYMOSTATIN A (3 entities in total)
• Functional Keywords: hydrolase (serine proteinase), hydrolase-hydrolase inhibitor complex, hydrolase/hydrolase inhibitor
• Biological source: Streptomyces griseus; More
• Total number of polymer chains: 2
• Total formula weight: 18624.33

Authors

Delbaere, L.T.J.,Brayer, G.D. (deposition date: 1986-04-18, release date: 1986-07-14, Last modification date: 2024-06-05)

Primary citation

Delbaere, L.T.,Brayer, G.D.
The 1.8 A structure of the complex between chymostatin and Streptomyces griseus protease A. A model for serine protease catalytic tetrahedral intermediates.
J.Mol.Biol., 183:89-103, 1985

PubMed Abstract: The naturally occurring serine protease inhibitor, chymostatin, forms a hemiacetal adduct with the catalytic Ser195 residue of Streptomyces griseus protease A. Restrained parameter least-squares refinement of this complex to 1.8 A resolution has produced an R index of 0 X 123 for the 11,755 observed reflections. The refined distance of the carbonyl carbon atom of the aldehyde to O gamma of Ser195 is 1 X 62 A. Both the R and S configurations of the hemiacetal occur in equal populations, with the end result resembling the expected configuration for a covalent tetrahedral product intermediate of a true substrate. This study strengthens the concept that serine proteases stabilize a covalent, tetrahedrally co-ordinated species and elaborates those features of the enzyme responsible for this effect. We propose that a major driving force for the hydrolysis of peptide bonds by serine proteases is the non-planar distortion of the scissile bond by the enzyme, which thereby lowers the activation energy barrier to hydrolysis by eliminating the resonance stabilization energy of the peptide bond.

PubMed: 3892018
DOI: 10.1016/0022-2836(85)90283-9

Experimental method

X-RAY DIFFRACTION (1.8 Å)