1cyu
SOLUTION NMR STRUCTURE OF RECOMBINANT HUMAN CYSTATIN A UNDER THE CONDITION OF PH 3.8 AND 310K
Structural highlights
DiseaseCYTA_HUMAN Defects in CSTA are the cause of ichthyosis exfoliative autosomal recessive ichthyosis bullosa of Siemens-like (AREI) [MIM:607936. A form of congenital exfoliative ichthyosis, sharing some features with ichthyosis bullosa of Siemens and annular epidermolytic ichthyosis. AREI presents shortly after birth as dry, scaly skin over most of the body with coarse peeling of non-erythematous skin on the palms and soles, which is exacerbated by excessive moisture and minor trauma. Electron microscopy analysis of skin biopsies, reveals mostly normal-appearing upper layers of the epidermis, but prominent intercellular edema of the basal and suprabasal cell layers with aggregates of tonofilaments in the basal keratinocytes.[1] FunctionCYTA_HUMAN This is an intracellular thiol proteinase inhibitor. Has an important role in desmosome-mediated cell-cell adhesion in the lower levels of the epidermis.[2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe solution structure of a human cystatin A variant, cystatin A2-98 M65L, which maintains the full inhibitory activity of the wild-type protein, was determined at pH 3.8 by sD/3D heteronuclear double- and triple-resonance NMR spectroscopy. The structure is based on a total of 1343 experimental restraints, comprising 1139 distance, 154 phi and chi 1 torsion angle restraints, and 50 distance constraints for 25 backbone hydrogen bonds. A total of 15 structures was calculated using the YASAP protocol with X-PLOR, and the atomic rms distribution about the mean coordinate positions for residues 8-93 was 0.55 +/- 0.10 A for the backbone atoms and 1.05 +/- 0.11 A for all heavy atoms. The structure consists of five antiparallel beta-sheets and two short alpha-helices. Comparison with the X-ray structure of cystatin B in the papain complex shows that the conformation of the first binding loop is quite similar to that of cystatin A, with an rms deviation of 0.78 A for the backbone atoms in the 43-53 region (cystatin A numbering). The second binding loop, however, is significantly different in the two structures, with an rms deviation greater than 2 A. There are some other significant differences, especially for the N-terminal and alpha-helix regions. The overall structure of cystatin A is also compared with the recently reported NMR structure of the wild-type cystatin A (stefin A) at pH 5.5 (Martin et al., 1995) and reveals the following features. that differ in our structure from the previous one: (1) the N-terminal segment, which was unstructured in the previous report, folds over in close vicinity to the C-terminus, as revealed by the distinctive NOEs between those segments; (2) two discrete short alpha-helices linked by a type II reverse turn were found, instead of the continuous single alpha-helix with a slight kink shown in the previous structure; (3) the second binding loop, which was not well converged in the previous study at pH 5.5, is determined very well in our structure. The effect of the N-terminal truncation on the cystatin A structure was examined by comparing the 1H-15N HSQC spectrum of cystatin A2-98 with that of the cystatin A5-98 variant, which lacks the anti-papain activity, revealing significant chemical shift differences in the residual N-terminal segment and the first binding loop, together with small shifts in the other parts.(ABSTRACT TRUNCATED AT 400 WORDS) Solution structure of a human cystatin A variant, cystatin A2-98 M65L, by NMR spectroscopy. A possible role of the interactions between the N- and C-termini to maintain the inhibitory active form of cystatin A.,Tate S, Ushioda T, Utsunomiya-Tate N, Shibuya K, Ohyama Y, Nakano Y, Kaji H, Inagaki F, Samejima T, Kainosho M Biochemistry. 1995 Nov 14;34(45):14637-48. PMID:7578072[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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