1KGM

SOLUTION STRUCTURE OF THE SMALL SERINE PROTEASE INHIBITOR SGCI

Summary for 1KGM

• Entry DOI: 10.2210/pdb1kgm/pdb
• Related: 1KIO 1KJ0 1PMC
• NMR Information: BMRB: 5272
• Descriptor: SERINE PROTEASE INHIBITOR I (1 entity in total)
• Functional Keywords: proteinase inhibitor, sgci, hydrolase
• Cellular location: Secreted: O46162
• Total number of polymer chains: 1
• Total formula weight: 3659.18

Authors

Gaspari, Z.,Patthy, A.,Graf, L.,Perczel, A. (deposition date: 2001-11-28, release date: 2001-12-12, Last modification date: 2024-11-06)

Primary citation

Gaspari, Z.,Patthy, A.,Graf, L.,Perczel, A.
Comparative structure analysis of proteinase inhibitors from the desert locust, Schistocerca gregaria.
Eur.J.Biochem., 269:527-537, 2002

PubMed Abstract: The solution structure of three small serine proteinase inhibitors, two natural and one engineered protein, SGCI (Schistocerca gregaria chymotrypsin inhibitor), SGCI[L30R, K31M] and SGTI (Schistocerca gregaria trypsin inhibitor), were determined by homonuclear NMR-spectroscopy. The molecules exhibit different specificities towards target proteinases, where SGCI is a good chymotrypsin inhibitor, its mutant is a potent trypsin inhibitor, and SGTI inhibits both proteinases weakly. Interestingly, SGTI is a much better inhibitor of insect proteinases than of the mammalian ones used in common assays. All three molecules have a similar fold composed from three antiparallel beta-pleated sheets with three disulfide bridges. The proteinase binding loop has a somewhat distinct geometry in all three peptides. Moreover, the stabilization of the structure is different in SGCI and SGTI. Proton-deuterium exchange experiments are indicative of a highly rigid core in SGTI but not in SGCI. We suggest that the observed structural properties play a significant role in the specificity of these inhibitors.

PubMed: 11856311
DOI: 10.1046/j.0014-2956.2001.02685.x

Experimental method

SOLUTION NMR