Please use this identifier to cite or link to this item:
Title: Structural basis for preferential Ca<sup>2+</sup>-displacement by a paramagnetic ion (Ce<sup>3+</sup>) in non-myristoylated neuronal calcium sensor-1
Authors: Chandra, Kousik
Susmitha, A L
Sharma, Y
Chary, K V R
Keywords: Bioinorganic chemistry
Neuronal calcium sensor
Calcium displacement
Issue Date: Mar-2011
Publisher: NISCAIR-CSIR, India
Abstract: We have investigated the Ca<sup>2+</sup>-displacement by a trivalent lanthanide ion (Ce<sup>3+</sup>) in a Ca<sup>2+</sup>-sensor protein called neuronal calcium sensor-1 in its non-myristoylated form by NMR. We observe that all the Ca<sup>2+</sup> bound to the three active Ca<sup>2+</sup>-binding loops are displaced by Ce<sup>3+</sup>. Microscopically, NMR paramagnetic titration data on [Ca<sup>2+</sup>]-non-myr-NCS-1 shows that the Ce<sup>3+</sup> displaces Ca<sup>2+</sup> first from both sites, EF2 and EF3, almost in parallel, followed by the displacement from EF4. Between EF2 and EF3, the NMR data conclusively shows that the Ca<sup>2+</sup>-displacement is more prominent in EF2 as compared to that in EF3. These findings have been attributed to: (i) the presence of a higher number of negatively charged residues in EF2 compared to EF3 and EF4, and, (ii) the presence of a Lys instead of a highly conserved Phe at –4 position in the first Ca<sup>2+</sup>-binding loop, which results in a relatively more open conformation of the N-terminal domain compared to the C-terminal counterpart.
Description: 539-547
ISSN: 0975-0975(Online); 0376-4710(Print)
Appears in Collections:IJC-A Vol.50A(03-04) [March-April 2011]

Files in This Item:
File Description SizeFormat 
IJCA 50A(03-04) 539-547.pdf339.88 kBAdobe PDFView/Open

Items in NOPR are protected by copyright, with all rights reserved, unless otherwise indicated.