TY - JOUR
T1 - Structural Basis for the Effects of Phenylalanine on Tuning the Reduction Potential of Type 1 Copper in Azurin
AU - Liu, Yiwei
AU - Marshall, Nicholas M.
AU - Yu, Sheng Song
AU - Kim, Wantae
AU - Gao, Yi Gui
AU - Robinson, Howard
AU - Nilges, Mark J.
AU - Zhang, Yan
AU - New, Siu Yee
AU - Lu, Yi
N1 - This work was supported by the National Science Foundation (CHE-2201279). We also thank the Robert A. Welch Foundation (Grant F-0020) for support of the Lu group research program at the University of Texas at Austin. Crystallographic data was acquired at the Advanced Light Source beamline 5.0.2 (proposal ALS-11565) of the Lawrence Berkeley National Laboratory, and the Advanced Photon Source beamline GM/CA 23-IDD (proposal 81327) of the Argonne National Laboratory. We thank Dr. Casey Van Stappen and Mr. Jingxiang Wang for proofreading this manuscript, Dr. Daniil Prigozhin at ALS and Dr. Craig Ogata at APS for their help in crystallography data collection, Dr. Zhenglin Yang and Dr. Nathaniel Miller for assisting in the ICP-MS experiments.
PY - 2023/7/24
Y1 - 2023/7/24
N2 - In order to investigate the effects of the secondary coordination sphere in fine-tuning redox potentials (E°′) of type 1 blue copper (T1Cu) in cupredoxins, we have introduced M13F, M44F, and G116F mutations both individually and in combination in the secondary coordination sphere of the T1Cu center of azurin (Az) from Pseudomonas aeruginosa. These variants were found to differentially influence the E°′ of T1Cu, with M13F Az decreasing E°′, M44F Az increasing E°′, and G116F Az showing a negligible effect. In addition, combining the M13F and M44F mutations increases E°′ by 26 mV relative to WT-Az, which is very close to the combined effect of E°′ by each mutation. Furthermore, combining G116F with either M13F or M44F mutation resulted in negative and positive cooperative effects, respectively. Crystal structures of M13F/M44F-Az, M13F/G116F-Az, and M44F/G116F-Az combined with that of G116F-Az reveal these changes arise from steric effects and fine-tuning of hydrogen bond networks around the copper-binding His117 residue. The insights gained from this study would provide another step toward the development of redox-active proteins with tunable redox properties for many biological and biotechnological applications.
AB - In order to investigate the effects of the secondary coordination sphere in fine-tuning redox potentials (E°′) of type 1 blue copper (T1Cu) in cupredoxins, we have introduced M13F, M44F, and G116F mutations both individually and in combination in the secondary coordination sphere of the T1Cu center of azurin (Az) from Pseudomonas aeruginosa. These variants were found to differentially influence the E°′ of T1Cu, with M13F Az decreasing E°′, M44F Az increasing E°′, and G116F Az showing a negligible effect. In addition, combining the M13F and M44F mutations increases E°′ by 26 mV relative to WT-Az, which is very close to the combined effect of E°′ by each mutation. Furthermore, combining G116F with either M13F or M44F mutation resulted in negative and positive cooperative effects, respectively. Crystal structures of M13F/M44F-Az, M13F/G116F-Az, and M44F/G116F-Az combined with that of G116F-Az reveal these changes arise from steric effects and fine-tuning of hydrogen bond networks around the copper-binding His117 residue. The insights gained from this study would provide another step toward the development of redox-active proteins with tunable redox properties for many biological and biotechnological applications.
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U2 - 10.1021/acs.inorgchem.3c01365
DO - 10.1021/acs.inorgchem.3c01365
M3 - Article
C2 - 37424080
AN - SCOPUS:85165546366
SN - 0020-1669
VL - 62
SP - 11618
EP - 11625
JO - Inorganic Chemistry
JF - Inorganic Chemistry
IS - 29
ER -