1GL1

structure of the complex between bovine alpha-chymotrypsin and PMP-C, an inhibitor from the insect Locusta migratoria

Summary for 1GL1

• Entry DOI: 10.2210/pdb1gl1/pdb
• Related: 1AB9 1ACB 1AFQ 1CA0 1CBW 1CGI 1CGJ 1CHG 1DLK 1EX3 1GCD 1GCT 1GG6 1GGD 1GHA 1GHB 1GL0 1GMC 1GMD 1GMH 1HJA 1MTN 1PMC 1VGC 2CGA 2GCH 2GCT 2GMT 2VGC 3GCH 3GCT 3VGC 4GCH 4VGC 5GCH 6GCH 7GCH 8GCH
• Descriptor: ALPHA-CHYMOTRYPSIN, PROTEASE INHIBITOR LCMI II, CADMIUM ION, ... (4 entities in total)
• Functional Keywords: hydrolase/inhibitor, complex (protease-inhibitor), hydrolase, serine protease, serine protease inhibitor, hydrolase-inhibitor complex
• Biological source: BOS TAURUS (BOVINE); More
• Cellular location: Secreted, extracellular space: P00766; Secreted: P80060
• Total number of polymer chains: 6
• Total formula weight: 89088.64

Authors

Roussel, A.,Kellenberger, C. (deposition date: 2001-08-22, release date: 2001-11-28, Last modification date: 2024-11-06)

Primary citation

Roussel, A.,Mathieu, M.,Dobbs, A.,Luu, B.,Cambillau, C.,Kellenberger, C.
Complexation of Two Proteic Insect Inhibitors to the Active Site of Chymotrypsin Suggests Decoupled Roles for Binding and Selectivity
J.Biol.Chem., 276:38893-, 2001

PubMed Abstract: The crystal structures of two homologous inhibitors (PMP-C and PMP-D2v) from the insect Locusta migratoria have been determined in complex with bovine alpha-chymotrypsin at 2.1- and 3.0-A resolution, respectively. PMP-C is a potent bovine alpha-chymotrypsin inhibitor whereas native PMP-D2 is a weak inhibitor of bovine trypsin. One unique mutation at the P1 position converts PMP-D2 into a potent bovine alpha-chymotrypsin inhibitor. The two peptides have a similar overall conformation, which consists of a triple-stranded antiparallel beta-sheet connected by three disulfide bridges, thus defining a novel family of serine protease inhibitors. They have in common the protease interaction site, which is composed of the classical protease binding loop (position P5 to P'4, corresponding to residues 26-34) and of an internal segment (residues 15-18), held together by two disulfide bridges. Structural divergences between the two inhibitors result in an additional interaction site between PMP-D2v (position P10 to P6, residues 21-25) and the residues 172-175 of alpha-chymotrypsin. This unusual interaction may be responsible for species selectivity. A careful comparison of data on bound and free inhibitors (from this study and previous NMR studies, respectively) suggests that complexation to the protease stabilizes the flexible binding loop (from P5 to P'4).

PubMed: 11495915
DOI: 10.1074/JBC.M105707200

Experimental method

X-RAY DIFFRACTION (2.1 Å)