3SGB

STRUCTURE OF THE COMPLEX OF STREPTOMYCES GRISEUS PROTEASE B AND THE THIRD DOMAIN OF THE TURKEY OVOMUCOID INHIBITOR AT 1.8 ANGSTROMS RESOLUTION

Replaces:  2SGBReplaces:  1SGB

Summary for 3SGB

• Entry DOI: 10.2210/pdb3sgb/pdb
• Descriptor: PROTEINASE B (SGPB), TURKEY OVOMUCOID INHIBITOR (OMTKY3) (3 entities in total)
• Functional Keywords: complex(serine proteinase-inhibitor)
• Biological source: Streptomyces griseus
• Cellular location: Secreted: P68390
• Total number of polymer chains: 2
• Total formula weight: 24692.10

Authors

Read, R.J.,Fujinaga, M.,Sielecki, A.R.,James, M.N.G. (deposition date: 1983-01-21, release date: 1983-07-12, Last modification date: 2024-10-30)

Primary citation

Read, R.J.,Fujinaga, M.,Sielecki, A.R.,James, M.N.
Structure of the complex of Streptomyces griseus protease B and the third domain of the turkey ovomucoid inhibitor at 1.8-A resolution.
Biochemistry, 22:4420-4433, 1983

PubMed Abstract: The structure of the complex between the serine protease Streptomyces griseus protease B (SGPB) and the third domain of the Kazal-type ovomucoid inhibitor from turkey has been solved at 1.8-A resolution and refined to a conventional R factor of 0.125. As others have reported previously for analogous complexes of proteases and protein inhibitors, the inhibitor binds in a fashion similar to that of a substrate; it is not cleaved, but there is a close approach (2.7 A) of the active site nucleophile Ser-195 O gamma to the carbonyl carbon of the reactive peptide bond of the inhibitor. Contrary to the structural reports regarding the other enzyme-inhibitor complexes, we conclude that there is no evidence for a significant distortion of this peptide bond from planarity. The mechanism of inhibition can be understood in terms of the equilibrium thermodynamic parameters Ka, the enzyme-inhibitor association constant, and Khyd, the equilibrium constant for inhibitor hydrolysis. These thermodynamic parameters can be rationalized in terms of the observed structure.

PubMed: 6414511
DOI: 10.1021/bi00288a012

Experimental method

X-RAY DIFFRACTION (1.8 Å)