Nature of the pH‐induced conformational changes and exposure of the C‐terminal region of chromogranin A

FEBS Letters

Ferretti, James A.²  Yoo, Seung Hyun¹ 

[1] Laboratory of Cellular Biology, National Institute on Deafness and Other Communication Disorders, Building 36, Room 5D-13, National Institutes of Health, Bethesda, MD 20892, USA;Laboratory of Biophysical Chemistry, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA

关键词: Chromogranin A;    Conformation;    pH;    C-terminal region;    CGA;    chromogranin A;    SDS-PAGE;    sodium dodecyl sulfate-polyacrylamide gel electrophoresis;    CD;    circular dichroism;    CAPS;    3-[cyclohexylamino]-1-propanesulfonic aicd;    PVDF;    polyvinylidene fluoride;   

DOI  :  10.1016/0014-5793(93)80715-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Chromogranin A is known to undergo pH induced conformational changes, and the difference in conformation is supposed to be responsible for the difference in Ca²⁺ binding property. To gain insight regarding the overall structure and the nature of pH-induced conformational changes of chromogranin A, limited trypsin digestions were carried out at pH 5.5 and pH 7.5. The resulting fragments were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the amino acid sequences of the tryptic fragments were determined. From these analyses it was shown that the chromogranin A structure consists of an N-terminal compact core region and a rather loosely organized C-terminal region and that the change of pH from 7.5 to 5.5 loosened the overall structure of chromogranin A, exposing the C-terminal region. Since the conserved C-terminal region (residues 407–431) was shown to exist in monomer-dimer and monomer-tetramer equilibria at pH 7.5 and 5.5, respectively, the conformational changes of the region at pH 7.5 and 5.5 were studied by circular dichroism spectroscopy using a synthetic peptide representing the conserved C-terminal region. When the pH was changed from 7.5 to 5.5, the coil structure of the C-terminal peptide decreased with an accompanying increase of α-helicity.

【 授权许可】

Unknown