Definition of the Interaction Domain for Cytochrome con Cytochrome c Oxidase

756

841

Recent investigations have shed much light on the nuclear and electronic factors that control the rates of long-range electron tunneling through molecules in aqueous and organic glasses as well as through bonds in donor-bridge-acceptor complexes. Couplings through covalent and hydrogen bonds are much stronger than those across van der Waals gaps, and these differences in coupling between bonded and nonbonded atoms account for the dependence of tunneling rates on the structure of the media between redox sites in Ru-modified proteins and protein-protein complexes.electron tunneling ͉ hopping ͉ glass ͉ protein

Section: Protein-protein Reactionsmentioning

confidence: 99%

Long-range electron transfer

Gray

Winkler

2005

756

841

“…The nDNA-encoded subunits provide a positively charged surface that probably interacts with the negatively charged part of the CYC dipole. More recently, extensive mutational analysis (16,21,26) and simulated binding of horse CYC to bovine COX (15) further demonstrated the importance of electrostatic interactions between CYC and COX. The electrostatic interactions participate in long-range protein-protein association and short-range orientation, such as through salt bridge formation (15).…”

mentioning

confidence: 99%

“…However, against this background of slow rates of CYC and COX evolution, upsurges in COX and CYC amino acid replacement rates occurred during the emergence and evolution of the larger brained primates (members of Anthropoidea) (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). Here, by using atomic resolution structural data on bovine COX (13) and horse CYC (14) and an experimentally verified model of the interaction between COX and CYC (15,16), we identify, among the Ͼ1,500 amino acid residues of COX, 57 residues that are likely to bind CYC during delivery of electrons to oxygen. We then demonstrate that the amino acid replacement rate acceleration in anthropoid lineages is especially pronounced in the subset of COX residues that can bind CYC.…”

mentioning

confidence: 99%

“…Accelerated rates in anthropoids were detected for two mtDNA-encoded subunits, COX1 and COX2; for seven nDNA-encoded COX subunits, COX4, COX5, COX6B, COX6C, COX7A, COX7C, and COX8; and for nDNA-encoded CYC (1-12, 17). Other studies pointed to the importance of electrostatic interactions between CYC and COX (16,(18)(19)(20)(21)(22) and indicated that the amino acid replacements in anthropoids altered the nature of the binding of CYC to COX (23).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Rapid electrostatic evolution at the binding site for cytochrome c on cytochrome c oxidase in anthropoid primates

Schmidt

Wildman

Uddin

et al. 2005

Cytochrome c (CYC) oxidase (COX), a multisubunit enzyme that functions in mitochondrial aerobic energy production, catalyzes the transfer of electrons from CYC to oxygen and participates in creating the electrochemical gradient used for ATP synthesis. Modeling three-dimensional structural data on COX and CYC reveals that 57 of the >1,500 COX residues can be implicated in binding CYC. Because of the functional importance of the transfer of electrons to oxygen, it might be expected that natural selection would drastically constrain amino acid replacement rates of CYC and COX. Instead, in anthropoid primates, although not in other mammals, CYC and COX show markedly accelerated amino acid replacement rates, with the COX acceleration being much greater at the positions that bind CYC than at those that do not. Specifically, in the anthropoid lineage descending from the last common ancestor of haplorhines (tarsiers and anthropoids) to that of anthropoids (New World monkeys and catarrhines) and that of catarrhines (Old World monkeys and apes, including humans), a minimum of 27 of the 57 COX amino acid residues that bind CYC were replaced, most frequently from electrostatically charged to noncharged residues. Of the COX charge-bearing residues involved in binding CYC, half (11 of 22) have been replaced with uncharged residues. CYC residues that interact with COX residues also frequently changed, but only two of the CYC changes altered charge. We suggest that reducing the electrostatic interaction between COX and CYC was part of the adaptive evolution underlying the emergence of anthropoid primates. mitochondria ͉ electron transport chain ͉ molecular coevolution C ytochrome c (CYC) and the subunits of CYC oxidase (COX) are mitochondrial-functioning proteins that play a central role in aerobic energy production. By catalyzing the transfer of electrons from CYC to oxygen, COX greatly increases an electrochemical gradient used for ATP synthesis. As a consequence of their critical function, mutations altering the structures of either CYC or COX must face the close scrutiny of natural selection. Among vertebrates, relatively few amino acid replacements have occurred in the structures of CYC and COX. However, against this background of slow rates of CYC and COX evolution, upsurges in COX and CYC amino acid replacement rates occurred during the emergence and evolution of the larger brained primates (members of Anthropoidea) (1-12). Here, by using atomic resolution structural data on bovine COX (13) and horse CYC (14) and an experimentally verified model of the interaction between COX and CYC (15, 16), we identify, among the Ͼ1,500 amino acid residues of COX, 57 residues that are likely to bind CYC during delivery of electrons to oxygen. We then demonstrate that the amino acid replacement rate acceleration in anthropoid lineages is especially pronounced in the subset of COX residues that can bind CYC. We further demonstrate that, among these CYC-binding COX residues, many amino acid replacements were from charge-bearing [electros...

“…uring June [16][17][18][19][20]1976, several hundred chemists and biologists assembled at the University of British Columbia (UBC) to listen to 13 lectures and discuss recent developments at the interface of inorganic chemistry and biology. To be sure, there had been many previous meetings at which this new science was featured, notably one in Blacksburg, Virginia (1), and several others on special topics that were held during the 1950s and 1960s.…”

mentioning

confidence: 99%

Biological inorganic chemistry at the beginning of the 21st century

Gray

2003

147

Advances in bioinorganic chemistry since the 1970s have been driven by three factors: rapid determination of high-resolution structures of proteins and other biomolecules, utilization of powerful spectroscopic tools for studies of both structures and dynamics, and the widespread use of macromolecular engineering to create new biologically relevant structures. Today, very large molecules can be manipulated at will, with the result that certain proteins and nucleic acids themselves have become versatile model systems for elucidating biological function.