2ci2
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(New page: 200px<br /><applet load="2ci2" size="450" color="white" frame="true" align="right" spinBox="true" caption="2ci2, resolution 2.0Å" /> '''CRYSTAL AND MOLECULAR...)
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Revision as of 07:00, 21 November 2007
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CRYSTAL AND MOLECULAR STRUCTURE OF THE SERINE PROTEINASE INHIBITOR CI-2 FROM BARLEY SEEDS
Overview
Chymotrypsin inhibitor 2 (CI-2), a serine proteinase inhibitor from barley, seeds, has been crystallized and its three-dimensional structure, determined at 2.0-A resolution by the molecular replacement method. The, structure has been refined by restrained-parameter least-squares methods, to a crystallographic R factor (= sigma parallel Fo magnitude of-Fo, parallel/sigma magnitude of Fo) o of 0.198. CI-2 is a member of the potato, inhibitor 1 family. It lacks the characteristic stabilizing disulfide, bonds of most other members of serine proteinase inhibitor families. The, body of CI-2 shows few conformational changes between the free inhibitor, and the previously reported structure of CI-2 in complex with subtilisin, Novo [McPhalen, C.A., Svendsen, I., Jonassen, I., & James, M.N.G. (1985), Proc. Natl. Acad. Sci. U.S.A. 82, 7242-7246]. However, the reactive site, loop has some significant conformational differences between the free, inhibitor and its complexed form. The residues in this segment of, polypeptide exhibit relatively large thermal motion parameters and some, disorder in the uncomplexed form of the inhibitor. The reactive site bond, is between Met-59I and Glu-60I in the consecutive sequential numbering of, CI-2 (Met-60-Glu-61 according to the alignment of Svendsen et al., [Svendsen, I., Hejgaard, J., & Chavan, J.K. (1984) Carlsberg Res. Commun., 49, 493-502]). The network of hydrogen bonds and electrostatic, interactions stabilizing the conformation of the reactive site loop is, much less extensive in the free than in the complexed inhibitor.
About this Structure
2CI2 is a Single protein structure of sequence from Hordeum vulgare. This structure superseeds the now removed PDB entry 1CI2. Full crystallographic information is available from OCA.
Reference
Crystal and molecular structure of the serine proteinase inhibitor CI-2 from barley seeds., McPhalen CA, James MN, Biochemistry. 1987 Jan 13;26(1):261-9. PMID:3828302
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