Mutants of Monomeric Red Fluorescent Protein mRFP1 at Residue 66: Structure Modeling by Molecular Dynamics and Search for Correlations with Spectral Properties

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E. E. Khrameeva¹, V. L. Drutsa², E. P. Vrzheshch¹, D. V. Dmitrienko³, and P. V. Vrzheshch^1,3*

¹Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119992 Moscow, Russia; fax: (495) 939-4218; E-mail: peter@genebee.msu.ru

²Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia; fax: (495) 938-2323; E-mail: drutsa@genebee.msu.ru

³International Biotechnological Center, Lomonosov Moscow State University, 119992 Moscow, Russia; fax: (495) 939-5022

^* To whom correspondence should be addressed.

Received February 4, 2008; Revision received March 17, 2008

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To study the interrelation between the spectral and structural properties of fluorescent proteins, structures of mutants of monomeric red fluorescent protein mRFP1 with all possible point mutations of Glu66 (except replacement by Pro) were simulated by molecular dynamics. A global search for correlations between geometrical structure parameters and some spectral characteristics (absorption maximum wavelength, integral extinction coefficient at the absorption maximum, excitation maximum wavelength, emission maximum wavelength, and quantum yield) was performed for the chromophore and its 6 Å environment in mRFP1, Q66A, Q66L, Q66S, Q66C, Q66H, and Q66N. The correlation coefficients (0.81-0.87) were maximal for torsion angles in phenolic and imidazolidine rings as well as for torsion angles in the regions of connection between these rings and chromophore attachment to β-barrel. The data can be used to predict the spectral properties of fluorescent proteins based on their structures and to reveal promising positions for directed mutagenesis.

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KEY WORDS: fluorescent proteins, mRFP1, mutants at residue 66, spectral characteristics, structure, correlations, molecular dynamics

DOI: 10.1134/S0006297908100040

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