A new idea that elucidates the electron carrier ability of plastocyanin (and o f azurin) is proposed. It emphasizes the fact that two lobes of the d-orbital. where one unpaired electron of copper (II) ion lies, are not screened by the ligand atoms, which would facilitate the electron transfer between the d-orbital and the redox partners (cytochrom e/ and P-700 in the case of plastocyanin). Seve...

New cationic Ag(I) complexes were prepared by reaction of AgBF4 with two thioether-functionalized bis(diphenylphosphino)amine ligands, Ph2PN(p-ArSMe)PPh2 (L1) and Ph2PN(n-PrSMe)PPh2 (L2), and compared with those obtained from the unfunctionalized ligands Ph2PN(Ph)PPh2 (L3) and Ph2PN(n-Bu)PPh2 (L4), respectively. The complex [Ag3(μ3-Cl)2(μ2-L1-P,P)3](BF4) (1·BF4) contains a triangular array of A...

X-ray structures at 3.0-3.1 A resolution of the cytochrome b(6) f complex from the cyanobacterium Mastigocladus laminosus [Kurisu, G., Zhang, H., Smith, J. L., and Cramer, W. A. (2003) Science 302, 1009-1014] and the green alga Chlamydomonas reinhardtii [Stroebel, D., Choquet, Y., Popot, J.-L., and Picot, D. (2003) Nature 426, 413-418] showed the presence of a unique heme, hemex, that is covale...

A series of new pentadentate thioether-oximes (TtoxH2, MeTtoxH2, OdtoxH2) were synthesized along with their Ni(II) and Cu(II) complexes. BF2 -bridging is accomplished by reaction of the H-bonded oxime complex with BF3·OEt2, though when Cu(BF4)2 is used as the Cu(II) salt, direct macrocyclization occurs during the metal complexation reaction. Crystallographic studies reveal: [Cu(TtoxH)]ClO4 has ...

An extensive series of ligand complexes of ferric cytochrome P-450-CAM has been examined by UV-visible absorption, magnetic circular dichroism, and electron paramagnetic resonance spectroscopy in an attempt to identify the ligand trans to cysteinate in the six-coordinate resting state of the enzyme. Thus, the ligands used have been chosen to serve as models for coordination by potential endogen...

Subtilosin A is a 35-residue, ribosomally synthesized bacteriocin encoded by the sbo-alb operon of Bacillus subtilis. It is composed of a head-to-tail circular peptide backbone that is additionally restrained by three unusual thioether bonds between three cysteines and the α-carbon of one threonine and two phenylalanines, respectively. In this study, we demonstrate that these bonds are synthesi...

Treatment of meso 2-ethylhexyl-3-mercaptopropionate substituted porphyrins with base at room temperature generated a porphyrin thiolate anion which in situ reacted in a nucleophilic aromatic substitution (SNAr) reaction with remaining thioether derivative. This reaction yielded S-linked bisporphyrins in good yields, with mechanistic insight obtained via displacement reactions. Additionally, SNA...