3cti

RELAXATION MATRIX REFINEMENT OF THE SOLUTION STRUCTURE OF SQUASH TRYPSIN INHIBITOR

spinqualitylabelsall models 3cti Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3cti is a 1 chain structure with sequence from Cucurbita maxima. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Solution NMR, 6 models Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function ITR1_CUCMA Inhibits trypsin. Publication Abstract from PubMed The structure of the small squash trypsin inhibitor CMTI-I is refined by directly minimizing the difference between the observed two-dimensional nuclear Overhauser enhancement (NOE) intensities and those calculated by the full relaxation matrix approach. To achieve this, a term proportional to this difference was added to the potential energy function of the molecular dynamics program X-PLOR. Derivatives with respect to atomic co-ordinates are calculated analytically. Spin diffusion effects are thus accounted for fully during the refinement. Initial structures for the refinement were those determined recently by solution nuclear magnetic resonance using the isolated two-spin approximation to derive distance range estimates. The fits to the nuclear magnetic resonance data improve significantly with only small shifts in the refined structures during a few cycles of conjugate gradient minimization. However, larger changes (approximately 1 A) in the conformation occur during simulated annealing, which is accompanied by a further reduction of the difference between experimental and calculated two-dimensional NOE intensities. The refined structures are closer to the X-ray structure of the inhibitor complexed with trypsin than the initial structures. The root-mean-square difference for backbone atoms between the initial structures and the X-ray structure is 0.96 A, and that between the refined structures and the X-ray structure 0.61 A. Relaxation matrix refinement of the solution structure of squash trypsin inhibitor.,Nilges M, Habazettl J, Brunger AT, Holak TA J Mol Biol. 1991 Jun 5;219(3):499-510. PMID:2051485 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Trypsin inhibitor 3D structures

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