1n4e

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spinqualitylabelsall models 1n4e, resolution 2.5Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Crystal Structure of a DNA Decamer Containing a Thymine-dimer

Overview

Two distinct dimerization contacts in calsequestrin crystals suggested a, mechanism for Ca(2+) regulation resulting from the occurrence of coupled, Ca(2+) binding and protein polymerization. Ca(2+)-induced formation of one, contact was proposed to lead to dimerization followed by Ca(2+)-induced, formation of the second contact to bring about polymerization (). To test, this mechanism, we compared canine cardiac calsequestrin and four, truncation mutants with regard to their folding properties, structures, and Ca(2+)-induced polymerization. The wild-type calsequestrin and, truncation mutants exhibited similar K(+)-induced folding and end-point, structures as indicated by intrinsic fluorescence and circular dichroism, respectively, whereas the polymerization tendencies of the wild-type, calsequestrin differed markedly from the polymerization tendencies of the, truncation mutants. Static laser light scattering and 3,3'-dithiobis, sulfosuccinimidyl-propionate cross-linking indicated that wild-type, protein exhibited an initial Ca(2+)-induced dimerization, followed by, additional oligomerization as the Ca(2+) concentration was raised or as, the K(+) concentration was lowered. None of the truncation mutants, exhibited clear stepwise oligomerization that depended on increasing, Ca(2+) concentration. Comparison of the three-dimensional structure of, rabbit skeletal calsequestrin with a homology model of canine cardiac, calsequestrin from the point of view of our coupled Ca(2+) binding and, polymerization mechanism leads to a possible explanation for the 2-fold, reduced Ca(2+) binding capacity of cardiac calsequestrin despite very, similar overall net negative charge for the two proteins.

About this Structure

1N4E is a Protein complex structure of sequences from [1]. The following page contains interesting information on the relation of 1N4E with [Thymine Dimers]. Full crystallographic information is available from OCA.

Reference

Polymerization of calsequestrin. Implications for Ca2+ regulation., Park H, Wu S, Dunker AK, Kang C, J Biol Chem. 2003 May 2;278(18):16176-82. Epub 2003 Feb 19. PMID:12594204

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