title: Reengineering cyt b562 for hydrogen production: A facile route to artificial hydrogenases.
abstract: Bioinspired, protein-based molecular catalysts utilizing base metals at the active are emerging as a promising avenue to sustainable hydrogen production. The protein matrix modulates the intrinsic reactivity of organometallic active sites by tuning second-sphere and long-range interactions. Here, we show that swapping Co-Protoporphyrin IX for Fe-Protoporphyrin IX in cytochrome b562 results in an efficient catalyst for photoinduced proton reduction to molecular hydrogen. Further, the activity of wild type Co-cyt b562 can be modulated by a factor of 2.5 by exchanging the coordinating methionine with alanine or aspartic acid. The observed turnover numbers (TON) range between 125 and 305, and correlate well with the redox potential of the Co-cyt b562 mutants. The photosensitized system catalyzes proton reduction with high efficiency even under an aerobic atmosphere, implicating its use for biotechnological applications. This article is part of a Special Issue entitled Biodesign for Bioenergetics--the design and engineering of electronic transfer cofactors, proteins and protein networks, edited by Ronald L. Koder and J.L. Ross Anderson.
authors.affiliation: Department of Chemistry and Biochemistry, Box 871604, Arizona State University, Tempe, AZ 85287-1604, USA. Electronic address: djsomme1@asu.edu.
authors.forename: Dayn Joseph
authors.initials: DJ
authors.lastname: Sommer
authors.affiliation: Department of Chemistry and Biochemistry, Box 871604, Arizona State University, Tempe, AZ 85287-1604, USA. Electronic address: mdvaughn@asu.edu.
authors.forename: Michael David
authors.initials: MD
authors.lastname: Vaughn
authors.affiliation: Department of Chemistry and Biochemistry, Box 871604, Arizona State University, Tempe, AZ 85287-1604, USA. Electronic address: bcclark1@asu.edu.
authors.forename: Brett Colby
authors.initials: BC
authors.lastname: Clark
authors.affiliation: Department of Chemistry and Biochemistry, Box 871604, Arizona State University, Tempe, AZ 85287-1604, USA. Electronic address: jjtomlin@asu.edu.
authors.forename: John
authors.initials: J
authors.lastname: Tomlin
authors.affiliation: Department of Chemistry and Biochemistry, Box 871604, Arizona State University, Tempe, AZ 85287-1604, USA. Electronic address: aroy10@uw.edu.
authors.forename: Anindya
authors.initials: A
authors.lastname: Roy
authors.affiliation: Department of Chemistry and Biochemistry, Box 871604, Arizona State University, Tempe, AZ 85287-1604, USA. Electronic address: gghirlanda@asu.edu.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Ghirlanda
mesh_terms: D002384:Catalysis; D020134:Catalytic Domain / Q000235:genetics; D003035:Cobalt / Q000737:chemistry / Q000378:metabolism; D003573:Cytochrome b Group / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D045304:Cytochromes c / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006859:Hydrogen / Q000378:metabolism*; D006864:Hydrogenase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D007501:Iron / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D016296:Mutagenesis; D011485:Protein Binding / Q000235:genetics; D015202:Protein Engineering / Q000379:methods*; D011524:Protoporphyrins / Q000737:chemistry / Q000378:metabolism; D058615:Synthetic Biology / Q000379:methods
chemical_list: D003573:Cytochrome b Group; D029968:Escherichia coli Proteins; D011524:Protoporphyrins; C017141:cobaltocytochrome c; D003035:Cobalt; D006859:Hydrogen; D045304:Cytochromes c; C017850:cytochrome b562, E coli; C028025:protoporphyrin IX; D007501:Iron; D006864:Hydrogenase
keywords: Cobalt catalysts; Fuel production; Protein engineering; Redox chemistry