1gd3: Difference between revisions
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'''refined solution structure of human cystatin A''' | '''refined solution structure of human cystatin A''' | ||
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[[Category: Shimba, N.]] | [[Category: Shimba, N.]] | ||
[[Category: Tate, S.]] | [[Category: Tate, S.]] | ||
[[Category: | [[Category: Cystatin some]] | ||
[[Category: | [[Category: Thiol protease inhibitor]] | ||
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Revision as of 17:26, 2 May 2008
refined solution structure of human cystatin A
OverviewOverview
The effect of substituting Pro25, located in the alpha-helical region of the cystatin A structure, with Ser has been studied. The structures of wild type and P25S cystatin A were determined by multidimensional NMR spectroscopy under comparable conditions. These two structures were virtually identical, and the alpha-helix between Glu15-Lys30 exists with uninterrupted continuity, with a slight bend at residue 25. In order to characterize the possible substitution effects of Pro25 with Ser on the alpha-helix, the chemical shifts of the amide nitrogens and protons, the generalized order parameters obtained by the analyses of the 15N-1H relaxation data, the amide proton exchange rates, and the NOE networks among the alpha-helical and surrounding residues were carefully compared. None of these parameters indicated any significant static or dynamic structural differences between the alpha-helical regions of the wild-type and P25S cystatin A proteins. We therefore conclude that our previous structure of the wild-type cystatin A, in which the alpha-helix exhibited a sharp kink at Pro25, must be revised. The asymmetric distribution of hydrophobic interactions between the side-chain residues of the alpha-helix and the rolled beta-sheet surface, as revealed by NOEs, may be responsible for the slight bend of the alpha-helix in both variants and for the destabilized hydrogen bonding of the alpha-helical residues that follow Pro25/Ser25, as evidenced by increased amide exchange rates.
About this StructureAbout this Structure
1GD3 is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
ReferenceReference
Structural comparison between wild-type and P25S human cystatin A by NMR spectroscopy. Does this mutation affect the alpha-helix conformation?, Shimba N, Kariya E, Tate S, Kaji H, Kainosho M, J Struct Funct Genomics. 2000;1(1):26-42. PMID:12836678 Page seeded by OCA on Fri May 2 17:26:01 2008