1kj0
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SOLUTION STRUCTURE OF THE SMALL SERINE PROTEASE INHIBITOR SGTI
OverviewOverview
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.
About this StructureAbout this Structure
1KJ0 is a Single protein structure of sequence from [1]. Full crystallographic information is available from OCA.
ReferenceReference
Comparative structure analysis of proteinase inhibitors from the desert locust, Schistocerca gregaria., Gaspari Z, Patthy A, Graf L, Perczel A, Eur J Biochem. 2002 Jan;269(2):527-37. PMID:11856311
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