Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Arch Biochem Biophys. 2014 Mar 1;545:9-21. doi: 10.1016/j.abb.2014.01.005. Epub 2014 Jan 13.

Folding and stability studies on C-PE and its natural N-terminal truncant.

Author information

  • 1Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia (Central University), Jamia Nagar, New Delhi 110 025, India.
  • 2BRD School of Biosciences, Sardar Patel University, Vallabh Vidyanagar, Gujarat 388 120, India.
  • 3Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia (Central University), Jamia Nagar, New Delhi 110 025, India. Electronic address: mihassan@jmi.ac.in.

Abstract

The conformational and functional state of biliproteins can be determined by optical properties of the covalently linked chromophores. α-Subunit of most of the phycoerythrin contains 164 residues. Recently determined crystal structure of the naturally truncated form of α-subunit of cyanobacterial phycoerythrin (Tr-αC-PE) lacks 31 N-terminal residues present in its full length form (FL-αC-PE). This provides an opportunity to investigate the structure-function relationship between these two natural forms. We measured guanidinium chloride (GdmCl)-induced denaturation curves of FL-αC-PE and Tr-αC-PE proteins, followed by observing changes in absorbance at 565nm, fluorescence at 350 and 573nm, and circular dichroism at 222nm. The denaturation curve of each protein was analyzed for ΔGD(∘), the value of Gibbs free energy change on denaturation (ΔGD) in the absence of GdmCl. The main conclusions of the this study are: (i) GdmCl-induced denaturation (native state↔denatured state) of FL-αC-PE and Tr-αC-PE is reversible and follows a two-state mechanism, (ii) FL-αC-PE is 1.4kcalmol(-1) more stable than Tr-αC-PE, (iii) truncation of 31-residue long fragment that contains two α-helices, does not alter the 3-D structure of the remaining protein polypeptide chain, protein-chromophore interaction, and (iv) amino acid sequence of Tr-αC-PE determines the functional structure of the phycoerythrin.

Copyright © 2014 Elsevier Inc. All rights reserved.

KEYWORDS:

Biliproteins; C-phycoerythrin; Chromophore; Folding and stability; Protein denaturation

PMID:
24434005
[PubMed - indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Write to the Help Desk