Variability of Calcium Binding to EF-hand Motifs Probed by Electrospray Ionization Mass Spectrometry

Moorthy, Anu K and Singh, SK and Gopal, B and Surolia, A and Murthy, MRN (2001) Variability of Calcium Binding to EF-hand Motifs Probed by Electrospray Ionization Mass Spectrometry. In: Journal of the American Society for Mass Spectrometry, 12 (12). pp. 1296-1301.

PDF Variability_of_Calcium_Binding_to.pdf - Published Version Restricted to Registered users only Download (209kB) | Request a copy

Abstract

The modulation of calcium binding by the EF-hand motifs present in a calmodulin (CAM) homologue, a calcium binding protein (CaBP) from Entamoeba histolytica by three external parameters-pH, ligand coordinator EGTA, and fragmentor voltage was investigated by mass spectrometry. Calcium binding follows expected patterns at highly acidic and alkaline pH with the preponderance of the apo and the completely saturated forms, respectively. Surprisingly, additional nonspecific binding is observed near neutral pH. Studies on EGTA chelation and effects of fragmentor voltage showed cooperativity in calcium removal in at least one of the domains. Similar studies on a smaller construct containing the two high affinity carboxy terminal sites revealed interesting differences and provided an estimate of the specificity and tolerance of the EF-hand motifs to calcium binding and removal. (C) 2001 American Society for Mass Spectrometry.

Item Type:	Journal Article
Publication:	Journal of the American Society for Mass Spectrometry
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	11 Feb 2010 06:31
Last Modified:	19 Sep 2010 04:59
URI:	http://eprints.iisc.ac.in/id/eprint/17952

Actions (login required)

View Item