6CWW

Cs H-NOX mutant with unnatural amino acid 4-cyano-L-phenylalanine at site 5

Summary for 6CWW

• Entry DOI: 10.2210/pdb6cww/pdb
• Descriptor: Methyl-accepting chemotaxis protein, PROTOPORPHYRIN IX CONTAINING FE, 2,2',2''-NITRILOTRIETHANOL, ... (4 entities in total)
• Functional Keywords: hnox, unnatural amino acid, nonnatural amino acid, gas binding, oxygen binding
• Biological source: Caldanaerobacter subterraneus
• Total number of polymer chains: 2
• Total formula weight: 47184.92

Authors

Kearney, C.,Olenginski, L.T.,Hirn, T.D.,Fowler, G.D.,Tariq, D.,Brewer, S.H.,Phillips-Piro, C.M. (deposition date: 2018-03-31, release date: 2018-05-16, Last modification date: 2024-10-30)

Primary citation

Kearney, C.,Olenginski, L.T.,Hirn, T.D.,Fowler, G.D.,Tariq, D.,Brewer, S.H.,Phillips-Piro, C.M.
Exploring local solvation environments of a heme protein using the spectroscopic reporter 4-cyano-l-phenylalanine.
RSC Adv, 8:13503-13512, 2018

PubMed Abstract: The vibrational reporter unnatural amino acid (UAA) 4-cyano-l-phenylalanine (pCNF) was genetically incorporated individually at three sites (5, 36, and 78) in the heme protein H-NOX to probe local hydration environments. The UAA pCNF was incorporated site-specifically using an engineered, orthogonal tRNA synthetase in . The ability of all of the pCNF-containing H-NOX proteins to form the ferrous CO, NO, or O ligated and unligated states was confirmed with UV-Vis spectroscopy. The solvation state at each site of the three sites of pCNF incorporation was assessed using temperature-dependent infrared spectroscopy. Specifically, the frequency-temperature line slope (FTLS) method was utilized to show that the nitrile group at site 36 was fully solvated and the nitrile group at site 78 was de-solvated (buried) in the heme pocket. The nitrile group at site 5 was found to be partially solvated suggesting that the nitrile group was involved in moderate strength hydrogen bonds. These results were confirmed by the determination of the X-ray crystal structure of the H-NOX protein construct containing pCNF at site 5.

PubMed: 29780583
DOI: 10.1039/c8ra02000k

Experimental method

X-RAY DIFFRACTION (1.851 Å)