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A Single Reactive Noncanonical Amino Acid Is Able to Dramatically Stabilize Protein Structure.

ABSTRACT: A p-isothiocyanate phenylalanine mutant of the homodimeric protein homoserine o-succinyltransferase (MetA) was isolated in a temperature dependent selection from a library of metA mutants containing noncanonical amino acids. This mutant protein has a dramatic increase of 24 °C in thermal stability compared to the wild type protein. Peptide mapping experiments revealed that the isothiocyanate group forms a thiourea cross-link to the N terminal proline of the other monomer, despite the two positions being >30 Å apart in the X-ray crystal structure of the wild type protein. These results show that an expanded set of building blocks beyond the canonical 20 amino acids can lead to significant changes in the properties of proteins.

SUBMITTER: Li JC

PROVIDER: S-EPMC6791372 | biostudies-literature | 2019 Jun

REPOSITORIES: biostudies-literature

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A Single Reactive Noncanonical Amino Acid Is Able to Dramatically Stabilize Protein Structure.

Li Jack C JC Nastertorabi Fariborz F Xuan Weimin W Han Gye Won GW Stevens Raymond C RC Schultz Peter G PG

ACS chemical biology 20190604 6

A p-isothiocyanate phenylalanine mutant of the homodimeric protein homoserine o-succinyltransferase (MetA) was isolated in a temperature dependent selection from a library of metA mutants containing noncanonical amino acids. This mutant protein has a dramatic increase of 24 °C in thermal stability compared to the wild type protein. Peptide mapping experiments revealed that the isothiocyanate group forms a thiourea cross-link to the N terminal proline of the other monomer, despite the two positio ...[more]

PMID: 31181898

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