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Comparative modeling of the three‐dimensional structure of the calmodulin‐related TCH2 protein from arabidopsis
Author(s) -
Khan Amir R.,
Johnson Keith A.,
Braam Janet,
James Michael N. G.
Publication year - 1997
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/(sici)1097-0134(199701)27:1<144::aid-prot14>3.0.co;2-n
Subject(s) - arabidopsis , calmodulin , linker , biophysics , gene , protein structure , gene product , computational biology , biology , chemistry , protein domain , biochemistry , microbiology and biotechnology , gene expression , computer science , mutant , enzyme , operating system
Plants adapt to various stresses by developmental alterations that render them less easily damaged. Expression of the TCH2 gene of Arabidopsis is strongly induced by stimuli such as touch and wind. The gene product, TCH2, belongs to the calmodulin (CaM) family of proteins and contains four highly conserved Ca 2+ ‐binding EF‐hands. We describe here the structure of TCH2 in the fully Ca 2+ ‐saturated form, constructed using comparative molecular modeling, based on the x‐ray structure of paramecium CaM. Like known CaMs, the overall structure consists of two globular domains separated by a linker helix. However, the linker region has added flexibility due to the presence of 5 glycines within a span of 6 residues. In addition, TCH2 is enriched in Lys and Arg residues relative to other CaMs, suggesting a preference for targets which are more negatively charged. Finally, a pair of Cys residues in the C‐terminal domain, Cys126 and Cys131, are sufficiently close in space to form a disulfide bridge. These predictions serve to direct future biochemical and structural studies with the overall aim of understanding the role of TCH2 in the cellular response of Arabidopsis to environmental stimuli. Proteins 27:144–153 © 1997 Wiley‐Liss, Inc.