Influence of tyrosine on the electronic circular dichroism of helical peptides

Samita Bhattacharjee, Gergely Tóth, Sándor Lovas, Jonathan D. Hirst

Research output: Contribution to journalArticle

34 Citations (Scopus)

Abstract

Studies of short helical peptides can provide insights into amino acid interactions in proteins and their role in protein folding. A common method of estimating helical structure is electronic circular dichroism (CD) in the far ultraviolet. It is known that aromatic side chains such as tyrosine may influence CD in this region, but this residue has desirable fluorescent properties and is nevertheless often incorporated into peptides. To investigate the relationship between the conformation of tyrosine and its contribution to the CD, we have calculated the CD of some short alanine-based helical peptides from first principles based on molecular dynamics simulations. The calculations are complemented by some analysis of static models. These theoretical studies estimate that a tyrosine residue may contribute up to ±5000 deg cm2 dmol-1 to the mean residue ellipticity at 220 nm, with the most typical value being 1000 deg cm2 dmol-1. If uncorrected, this would lead to an underestimate of the helicity of the peptide of 5-20%. For a tyrosine side chain in the trans rotameric state, there is a discernible relationship between its precise orientation and its contribution to CD at 220 nm. Experiments on tyrosine-containing peptides using CD should be interpreted bearing these findings in mind and, preferably, with an independent approach for probing the conformational states of tyrosine.

Original languageEnglish
Pages (from-to)8682-8688
Number of pages7
JournalJournal of Physical Chemistry B
Volume107
Issue number33
StatePublished - Aug 21 2003

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tyrosine
Dichroism
Peptides
dichroism
peptides
Tyrosine
electronics
Bearings (structural)
proteins
Protein folding
static models
ellipticity
alanine
Alanine
folding
Electronic structure
amino acids
Conformations
Molecular dynamics
Amino acids

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry

Cite this

Influence of tyrosine on the electronic circular dichroism of helical peptides. / Bhattacharjee, Samita; Tóth, Gergely; Lovas, Sándor; Hirst, Jonathan D.

In: Journal of Physical Chemistry B, Vol. 107, No. 33, 21.08.2003, p. 8682-8688.

Research output: Contribution to journalArticle

Bhattacharjee, S, Tóth, G, Lovas, S & Hirst, JD 2003, 'Influence of tyrosine on the electronic circular dichroism of helical peptides', Journal of Physical Chemistry B, vol. 107, no. 33, pp. 8682-8688.
Bhattacharjee, Samita ; Tóth, Gergely ; Lovas, Sándor ; Hirst, Jonathan D. / Influence of tyrosine on the electronic circular dichroism of helical peptides. In: Journal of Physical Chemistry B. 2003 ; Vol. 107, No. 33. pp. 8682-8688.
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