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Ester carbonyl vibration as a sensitive probe of protein local electric field.

ABSTRACT: The ability to quantify the local electrostatic environment of proteins and protein/peptide assemblies is key to gaining a microscopic understanding of many biological interactions and processes. Herein, we show that the ester carbonyl stretching vibration of two non-natural amino acids, L-aspartic acid 4-methyl ester and L-glutamic acid 5-methyl ester, is a convenient and sensitive probe in this regard, since its frequency correlates linearly with the local electrostatic field for both hydrogen-bonding and non-hydrogen-bonding environments. We expect that the resultant frequency-electric-field map will find use in various applications. Furthermore, we show that, when situated in a non-hydrogen-bonding environment, this probe can also be used to measure the local dielectric constant (?). For example, its application to amyloid fibrils formed by A?(16-22) revealed that the interior of such ?-sheet assemblies has an ??value of approximately 5.6.

SUBMITTER: Pazos IM

PROVIDER: S-EPMC4104746 | biostudies-literature | 2014 Jun

REPOSITORIES: biostudies-literature

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Ester carbonyl vibration as a sensitive probe of protein local electric field.

Pazos Ileana M IM Ghosh Ayanjeet A Tucker Matthew J MJ Gai Feng F

Angewandte Chemie (International ed. in English) 20140430 24

The ability to quantify the local electrostatic environment of proteins and protein/peptide assemblies is key to gaining a microscopic understanding of many biological interactions and processes. Herein, we show that the ester carbonyl stretching vibration of two non-natural amino acids, L-aspartic acid 4-methyl ester and L-glutamic acid 5-methyl ester, is a convenient and sensitive probe in this regard, since its frequency correlates linearly with the local electrostatic field for both hydrogen ...[more]

PMID: 24788907

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