Download MendeleyComparative structure analysis of proteinase inhibitors from the desert locust, Schistocerca gregaria.
Gaspari, Z., Patthy, A., Graf, L., Perczel, A.(2002) Eur J Biochem 269: 527-537
- PubMed: 11856311
- DOI: https://doi.org/10.1046/j.0014-2956.2001.02685.x
- Primary Citation of Related Structures:
1KGM, 1KIO, 1KJ0 - 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.
Organizational Affiliation:
Department of Organic Chemistry, Eötvös L University, Budapest, Hungary.
