Organization and dynamics of the N-terminal domain of chemokine receptor CXCR1 in reverse micelles

Effect of graded hydration

Arunima Chaudhuri, Pritam Basu, Sourav Haldar, Mamata Kombrabail, G. Krishnamoorthy, Krishna Rajarathnam, Amitabha Chattopadhyay

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Water plays a fundamental role in the folding, structure, dynamics, and function of proteins and peptides. The extracellular N-terminal domain of chemokine receptors is crucial in mediating binding affinity, receptor selectivity, and regulating function. The flexible N-terminal domain becomes ordered in membranes and membrane-mimetic assemblies, thereby indicating that the membrane could play an important role in regulating CXC chemokine receptor 1 (CXCR1) function. In view of the role of hydration in lipid-protein interactions in membranes, we explored the organization and dynamics of a 34-mer peptide of the CXCR1 N-terminal domain in reverse micelles by utilizing a combination of fluorescence-based approaches and circular dichroism spectroscopy. Our results show that the secondary structure adopted by the CXCR1 N-domain is critically dependent on hydration. The tryptophan residues of the CXCR1 N-domain experience motional restriction and exhibit red edge excitation shift (REES) upon incorporation in reverse micelles. REES and fluorescence lifetime exhibit reduction with increasing reverse micellar hydration. Time-resolved fluorescence anisotropy measurements reveal the effect of hydration on peptide rotational dynamics. Taken together, these results constitute the first report demonstrating modulation in the organization and dynamics of the N-terminal domain of a chemokine receptor in a membrane-like environment of varying hydration. We envisage that these results are relevant in the context of hydration in the function of G protein-coupled receptors.

Original languageEnglish (US)
Pages (from-to)1225-1233
Number of pages9
JournalJournal of Physical Chemistry B
Volume117
Issue number5
DOIs
StatePublished - Feb 7 2013

Fingerprint

Interleukin-8A Receptors
Micelles
Hydration
hydration
micelles
Membranes
Peptides
membranes
Chemokine Receptors
Fluorescence
peptides
Proteins
proteins
fluorescence
Circular dichroism spectroscopy
folding structures
G-Protein-Coupled Receptors
Tryptophan
Lipids
shift

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Materials Chemistry
  • Surfaces, Coatings and Films

Cite this

Organization and dynamics of the N-terminal domain of chemokine receptor CXCR1 in reverse micelles : Effect of graded hydration. / Chaudhuri, Arunima; Basu, Pritam; Haldar, Sourav; Kombrabail, Mamata; Krishnamoorthy, G.; Rajarathnam, Krishna; Chattopadhyay, Amitabha.

In: Journal of Physical Chemistry B, Vol. 117, No. 5, 07.02.2013, p. 1225-1233.

Research output: Contribution to journalArticle

Chaudhuri, Arunima ; Basu, Pritam ; Haldar, Sourav ; Kombrabail, Mamata ; Krishnamoorthy, G. ; Rajarathnam, Krishna ; Chattopadhyay, Amitabha. / Organization and dynamics of the N-terminal domain of chemokine receptor CXCR1 in reverse micelles : Effect of graded hydration. In: Journal of Physical Chemistry B. 2013 ; Vol. 117, No. 5. pp. 1225-1233.
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