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C-Terminal Half of Human Centrin 2 Behaves like a Regulatory EF-Hand Domain

Authors :
Patricia Duchambon
Yves Blouquit
Jos A. Cox
Simona Miron
Isabelle Durussel
Elena Matei
Constantin T. Craescu
Source :
Biochemistry. 42:1439-1450
Publication Year :
2003
Publisher :
American Chemical Society (ACS), 2003.

Abstract

Human centrin 2 (HsCen2) is an EF-hand protein that plays a critical role in the centrosome duplication and separation during cell division. We studied the structural and Ca(2+)-binding properties of two C-terminal fragments of this protein: SC-HsCen2 (T94-Y172), covering two EF-hands, and LC-HsCen2 (M84-Y172), having 10 additional residues. Both fragments are highly disordered in the apo state but become better structured (although not conformationally homogeneous) in the presence of Ca(2+) and depending on the nature of the cations (K(+) or Na(+)) in the buffer. Only the longer C-terminal domain, in the Ca(2+)-saturated state and in the presence of Na(+) ions, was amenable to structure determination by nuclear magnetic resonance. The solution structure of LC-HsCen2 reveals an open two EF-hand structure, similar to the conformation of related Ca(2+)-saturated regulatory domains. Unexpectedly, the N-terminal helix segment (F86-T94) lies over the exposed hydrophobic cavity. This unusual intramolecular interaction increases considerably the Ca(2+) affinity and constitutes a useful model for the target binding.

Details

ISSN :
15204995 and 00062960
Volume :
42
Database :
OpenAIRE
Journal :
Biochemistry
Accession number :
edsair.doi.dedup.....882f2177056ffef12832c99ccb0a56d2
Full Text :
https://doi.org/10.1021/bi0269714