6MTG

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

Summary for 6MTG

• Entry DOI: 10.2210/pdb6mtg/pdb
• Descriptor: Homoserine O-succinyltransferase, DI(HYDROXYETHYL)ETHER, FORMIC ACID, ... (5 entities in total)
• Functional Keywords: noncanonical amino acid, isothiocyanate, crosslink, thiourea, stabilization, transferase
• Biological source: Escherichia coli (strain K12)
• Total number of polymer chains: 2
• Total formula weight: 70703.12

Authors

Li, J.C.,Nasertorabi, F.,Xuan, W.,Han, G.W.,Stevens, R.C.,Schultz, P.G. (deposition date: 2018-10-19, release date: 2019-06-26, Last modification date: 2024-11-06)

Primary citation

Li, J.C.,Nastertorabi, F.,Xuan, W.,Han, G.W.,Stevens, R.C.,Schultz, P.G.
A Single Reactive Noncanonical Amino Acid Is Able to Dramatically Stabilize Protein Structure.
Acs Chem.Biol., 14:1150-1153, 2019

PubMed 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.

PubMed: 31181898
DOI: 10.1021/acschembio.9b00002

Experimental method

X-RAY DIFFRACTION (1.85 Å)