TY - JOUR
T1 - Construction of heterometallic clusters in a small peptide scaffold as [NiFe]-hydrogenase models
T2 - Development of a synthetic methodology
AU - Dutta, Arnab
AU - Hamilton, G. Alexander
AU - Hartnett, Hilairy
AU - Jones, Anne
PY - 2012/9/17
Y1 - 2012/9/17
N2 - [NiFe]-hydrogenases are enzymes that catalyze the reversible interconversion of protons and hydrogen at a heterobimetallic site containing Ni and Fe. This organometallic site has served as an inspiration for the synthesis of a number of biomimetic complexes, but, unfortunately, most close structural mimics have shown little to no reactivity with either of the substrates for hydrogenases. This suggests that interactions between the metallo-active site and the protein scaffold are crucial in tuning reactivity. As a first step toward development of peptide-based models, in this paper we demonstrate a synthetic strategy for construction of peptide coordinated, cysteinyl thiolate bridged Ni-M complexes in which M is a hetero-organometallic fragment. We utilize the seven amino acid peptide ACDLPCG as a scaffold for construction of these peptide-coordinated metallocenters. This peptide binds Ni in an N 2S2 environment consisting of the amino terminus, an amide nitrogen, and the two cysteinyl thiolates. We show that these thiolates serve as reactive sites for formation of heterometallic complexes in which they serve as bridging ligands. The method is general, and a number of heterometallic fragments including Ru(η6-arene)2+, M(CO) 4(piperidine) for M = Mo and W, and Fe2(CO)6 were successfully incorporated, and the resulting metallopeptides characterized via a range of spectroscopic techniques. This methodology serves as the first step to construction of hydrogenase peptidomimetics that incorporate defined outer coordination sphere interactions intended to tune reactivity.
AB - [NiFe]-hydrogenases are enzymes that catalyze the reversible interconversion of protons and hydrogen at a heterobimetallic site containing Ni and Fe. This organometallic site has served as an inspiration for the synthesis of a number of biomimetic complexes, but, unfortunately, most close structural mimics have shown little to no reactivity with either of the substrates for hydrogenases. This suggests that interactions between the metallo-active site and the protein scaffold are crucial in tuning reactivity. As a first step toward development of peptide-based models, in this paper we demonstrate a synthetic strategy for construction of peptide coordinated, cysteinyl thiolate bridged Ni-M complexes in which M is a hetero-organometallic fragment. We utilize the seven amino acid peptide ACDLPCG as a scaffold for construction of these peptide-coordinated metallocenters. This peptide binds Ni in an N 2S2 environment consisting of the amino terminus, an amide nitrogen, and the two cysteinyl thiolates. We show that these thiolates serve as reactive sites for formation of heterometallic complexes in which they serve as bridging ligands. The method is general, and a number of heterometallic fragments including Ru(η6-arene)2+, M(CO) 4(piperidine) for M = Mo and W, and Fe2(CO)6 were successfully incorporated, and the resulting metallopeptides characterized via a range of spectroscopic techniques. This methodology serves as the first step to construction of hydrogenase peptidomimetics that incorporate defined outer coordination sphere interactions intended to tune reactivity.
UR - http://www.scopus.com/inward/record.url?scp=84866391655&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84866391655&partnerID=8YFLogxK
U2 - 10.1021/ic2026818
DO - 10.1021/ic2026818
M3 - Article
C2 - 22924594
AN - SCOPUS:84866391655
SN - 0020-1669
VL - 51
SP - 9580
EP - 9588
JO - Inorganic chemistry
JF - Inorganic chemistry
IS - 18
ER -