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Isotope-Labeled Aspartate Sidechain as a Non-Perturbing Infrared Probe: Application to Investigate the Dynamics of a Carboxylate Buried Inside a Protein.

ABSTRACT: Because of their negatively charged carboxylates, aspartate and glutamate are frequently found at the active or binding site of proteins. However, studying a specific carboxylate in proteins that contain multiple aspartates and/or glutamates via infrared spectroscopy is difficult due to spectral overlap. We show, herein, that isotopic-labeling of the aspartate sidechain can overcome this limitation as the resultant 13C=O asymmetric stretching vibration resides in a transparent region of the protein IR spectrum. Applicability of this site-specific vibrational probe is demonstrated by using it to assess the dynamics of an aspartate ion buried inside a small protein via two-dimensional infrared spectroscopy.

SUBMITTER: Abaskharon RM

PROVIDER: S-EPMC5638131 | biostudies-literature | 2017 Sep

REPOSITORIES: biostudies-literature

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Isotope-Labeled Aspartate Sidechain as a Non-Perturbing Infrared Probe: Application to Investigate the Dynamics of a Carboxylate Buried Inside a Protein.

Abaskharon Rachel M RM Brown Stephen P SP Zhang Wenkai W Chen Jianxin J Smith Amos B AB Gai Feng F

Chemical physics letters 20170323

Because of their negatively charged carboxylates, aspartate and glutamate are frequently found at the active or binding site of proteins. However, studying a specific carboxylate in proteins that contain multiple aspartates and/or glutamates via infrared spectroscopy is difficult due to spectral overlap. We show, herein, that isotopic-labeling of the aspartate sidechain can overcome this limitation as the resultant <sup>13</sup>C=O asymmetric stretching vibration resides in a transparent region ...[more]

PMID: 29033461

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