Pandey, Kalpana and Dhoke, Reema R and Rathore, Yogendra Singh and Nath, Samir K and Verma, Neha and Bawa, Simranjot and Ganguly, Ashish (2014) Low pH overrides the need of calcium ions for the shape-function relationship of calmodulin: resolving prevailing debates. The journal of physical chemistry. B, 118 (19). pp. 5059-74. ISSN 1520-5207
Full text not available from this repository. (Request a copy)Abstract
Calmodulin (CaM) regulates numerous cellular functions by sensing Ca(2+) levels inside cells. Although its structure as a function of the Ca(2+)-bound state remains hotly debated, no report is available on how pH independently or in interaction with Ca(2+) ions regulates shape and function of CaM. From SAXS data analysis of CaM at different levels of Ca(2+)-ion concentration and buffer pH, we found that (1) CaM molecules possess a Gaussian-chain-like shape in solution even in the presence of Ca(2+) ion or at low pH, (2) the global shape of apo CaM is very similar to its NMR structure rather than the crystal structures, (3) about 16 Ca(2+) ions or more are required per CaM molecule in solution to achieve the four-Ca(2+)-bound crystal structure, (4) low pH alone can impart shape changes in CaM similar to Ca(2+) ions, and (5) at different [Ca(2+)]/[CaM] ratio or pH values, the predominant shape of CaM is essentially a weighted average of its apo and fully activated shape. Results were further substantiated by analysis of sedimentation coefficient values from analytical ultracentrifugation and peptide binding assays using two peptides, each known to preferentially bind the apo or the Ca(2+)-activated state.
| Item Type: | Article |
|---|---|
| Depositing User: | Dr. K.P.S.Sengar |
| Date Deposited: | 09 Feb 2015 10:47 |
| Last Modified: | 22 Jul 2015 03:43 |
| URI: | http://crdd.osdd.net/open/id/eprint/1560 |
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