Abstract:
:Recent structural studies of the HMG-CoA synthase members of the thiolase superfamily have shown that the catalytic loop containing the nucleophilic cysteine follows the phi and psi angle pattern of a II' beta turn. However, the i + 1 residue is conserved as an alanine, which is quite unusual in this position as it must adopt a strained positive phi angle to accommodate the geometry of the turn. To assess the effect of the conserved strain in the catalytic loop, alanine 110 of Enterococcus faecalis 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) synthase was mutated to a glycine. Subsequent enzymatic studies showed that the overall reaction rate of the enzyme was increased 140-fold. An X-ray crystallographic study of the Ala110Gly mutant enzyme demonstrated unanticipated adjustments in the active site that resulted in additional stabilization of all three steps of the reaction pathway. The rates of acetylation and hydrolysis of the mutant enzyme increased because the amide nitrogen of Ser308 shifts 0.4 A toward the catalytic cysteine residue. This motion positions the nitrogen to better stabilize the intermediate negative charge that develops on the carbonyl oxygen of the acetyl group during both the formation of the acyl-enzyme intermediate and its hydrolysis. In addition, the hydroxyl of Ser308 rotates 120 degrees to a position where it is able to stabilize the carbanion intermediate formed by the methyl group of the acetyl-S-enzyme during its condensation with acetoacetyl-CoA.
journal_name
Biochemistryjournal_title
Biochemistryauthors
Steussy CN,Robison AD,Tetrick AM,Knight JT,Rodwell VW,Stauffacher CV,Sutherlin ALdoi
10.1021/bi061505qsubject
Has Abstractpub_date
2006-12-05 00:00:00pages
14407-14issue
48eissn
0006-2960issn
1520-4995journal_volume
45pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract::The actinomycin biosynthetic gene cluster of Streptomyces chrysomallus harbors two paralogous genes, acmI and acmL, encoding methyltransferases. To unveil their suspected role in the formation of 3-hydroxy-4-methyl-anthranilic acid (4-MHA), the building block of the actinomycin chromophore, each gene was expressed in ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi101422r
更新日期:2010-11-16 00:00:00
abstract::Phosphatase of regenerating liver 3 (PRL-3) is suggested as a biomarker and therapeutic target in several cancers. It has a well-established causative role in cancer metastasis. However, little is known about its natural substrates, pathways, and biological functions, and only a few protein substrates have been sugges...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi201095z
更新日期:2011-09-06 00:00:00
abstract::We have used electron spin resonance and circular dichroism to examine and compare the dynamics in two analogues of the Ala-based 3K(I) peptide [Marqusee, S., Robbins, V.H., & Baldwin, R. L. (1989) Proc. Natl. Acad. Sci. U.S.A. 86, 5286-5290], labeled at positions 4 and 8, throughout the alpha-helix----coil transition...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00103a016
更新日期:1991-10-01 00:00:00
abstract::Experimental and theoretical double-mutant cycles have been used to investigate a salt bridge in the N-terminal domain of the protein L9. Aspartic acid 23 is the only acidic residue involved in a well-defined pairwise interaction, namely, a partially solvent-exposed salt bridge with the protonated N-terminus of the pr...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi027202n
更新日期:2003-06-17 00:00:00
abstract::Clostridial neurotoxins are zinc endopeptidases, and each contains one Zn(2+)/molecule. To investigate the structural/functional role of Zn(2+) in botulinum neurotoxin light chain (the enzymatic subunit of the neurotoxin), the effect of the removal of zinc on protein folding and enzyme kinetics was investigated. The a...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0007472
更新日期:2000-08-29 00:00:00
abstract::Frequency-domain fluorescence resonance energy transfer and anisotropy measurements were performed to characterize conformational dynamics of an analog of the RNase S-peptide (residues 1-20). Trp was used as a donor by replacing Phe 8, and a dansyl acceptor group was introduced at position 1 or 18. The distance-distri...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00097a009
更新日期:1993-11-23 00:00:00
abstract::These investigations characterize the covalent binding of reactive products of prostaglandin H-synthases (PGHSs) to the enzyme and to other molecules. The intermediate product of oxygenation of arachidonic acid by the PGHSs, prostaglandin (PG) H2, undergoes rearrangement to the highly reactive gamma-keto aldehydes, le...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi002629k
更新日期:2001-06-12 00:00:00
abstract::Lysyl-tRNA synthetase, a class II enzyme, edits homocysteine by converting it into homocysteine thiolactone. In a similar reaction, the enzyme converts homoserine into homoserine lactone. Other class II enzymes, aspartyl-tRNA synthetase and seryl-tRNA synthetase, do not edit any of the amino acids tested. However, all...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi970589n
更新日期:1997-09-16 00:00:00
abstract::Oxygen binding by Octopus dofleini hemocyanin was examined under very nearly physiological conditions. The effects of pH, ionic composition, temperature, and aggregation were controlled so that the role each plays in modulating oxygen binding can be isolated. There is a very large effect of pH on affinity, the Bohr ef...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00338a015
更新日期:1985-08-13 00:00:00
abstract::The backbone dynamics of the liganded (holo) and unliganded (apo) forms of Escherichia coli-derived rat intestinal fatty acid-binding protein (I-FABP) have been characterized and compared using amide 15N relaxation and 1H exchange NMR measurements. The amide 1H/15N resonances for apo and holo I-FABP were assigned at 2...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi962018l
更新日期:1997-02-25 00:00:00
abstract::Thermodynamic equilibrium transition models in DSC are only applicable to reversible processes, but reversibility of the thermal transitions of proteins is comparatively rare because of intermolecular aggregation of denatured proteins and the degradation that occurs at high temperatures. The cupredoxin azurin from Pse...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0157621
更新日期:2002-01-22 00:00:00
abstract::The association between the papillomavirus E1 and E2 proteins is an important regulatory interaction, imparting coordinated control of viral transcription and replication. Using fluorescence polarization, we have characterized the interactions between HPV-11 E1, HPV-11 E2, and DNA in solution at equilibrium. For these...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi982616v
更新日期:1999-04-06 00:00:00
abstract::Glutamine 143 in human manganese superoxide dismutase (MnSOD) forms a hydrogen bond with the manganese-bound solvent molecule and is investigated by replacement using site-specific mutagenesis. Crystal structures showed that the replacement of Gln 143 with Ala made no significant change in the overall structure of the...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9929958
更新日期:2000-06-20 00:00:00
abstract::Known crystal structures of class II aminoacyl-tRNA synthetases complexed to their cognate tRNAs reveal that critical acceptor stem contacts are made by the variable loop connecting the beta-strands of motif 2 located within the catalytic core of class II synthetases. To identify potential acceptor stem contacts made ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi001835p
更新日期:2000-12-19 00:00:00
abstract::Manganese superoxide dismutase (MnSOD) cycles between the Mn(II) and Mn(III) states during the catalyzed disproportionation of O(2)(*-), a catalysis that is limited at micromolar levels of superoxide by a peroxide-inhibited complex with the metal. We have investigated the role in catalysis and inhibition of the conser...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi011047f
更新日期:2001-10-09 00:00:00
abstract::Phenylcarbene and adamantylidene have been generated photochemically from the corresponding diazirines within lipid bilayers. Reasonable yields of labeled fatty acid side chains have been observed. The products have been characterized by gas chromatography-mass spectrometry and derive both from the insertion of the c...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00605a026
更新日期:1978-06-13 00:00:00
abstract::Octaprenyl pyrophosphate synthase (OPPs) catalyzes consecutive condensation reactions of farnesyl pyrophosphate (FPP) with five molecules of isopentenyl pyrophosphate (IPP) to generate C(40) octaprenyl pyrophosphate (OPP) which constitutes the side chain of menaquinone. We have previously reported the X-ray structure ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi036336d
更新日期:2004-06-22 00:00:00
abstract::A strategy to design potent antagonists of human coagulation factor VIIa (FVIIa) by linking two proteins that independently inhibit activity and bind at separate, nonoverlapping sites is presented. A bifunctional inhibitor (KDTF5), comprising a Kunitz-type domain engineered to inhibit the FVIIa active site and a solub...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi970388j
更新日期:1997-05-13 00:00:00
abstract::Protein C is a vitamin K dependent protein present in bovine plasma (Stenflo, J. (1976), J. Biol. Chem. 251, 355). It is a glycoprotein (mol wt approximately 62 000) composed of a heavy chain (mol wt 41 000) and a light chain (mol wt 21 000). The heavy chain has an amino-terminal sequence of Asp-Thr-Asn-Gln and contai...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00667a022
更新日期:1976-11-02 00:00:00
abstract::A detailed study has been made of the polyacrylamide gel electrophoresis of DNA restriction fragments obtained from two plasmids, pBR322 and p82-6B. Variables studied were molecular weight, gel concentration, temperature, and electric field strength. The retardation coefficients of the larger fragments (greater than 8...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00295a023
更新日期:1983-12-20 00:00:00
abstract::Nicotinic acetylcholine receptors (nAChRs) were studied in detail in the past regarding their interaction with therapeutic and drug addiction related compounds. Using fast kinetic whole-cell recording, we have now studied effects of tacrine, an agent used clinically to treat Alzheimer's disease, on currents elicited b...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi101789y
更新日期:2011-03-22 00:00:00
abstract::R67 dihydrofolate reductase (DHFR) is an R-plasmid encoded enzyme that confers resistance to the antibacterial drug trimethoprim. This enzyme is not homologous in sequence or structure to chromosomal DHFRs. Equilibrium folding of tetrameric R67 DHFR was studied and found to be fully reversible. Formation of an inactiv...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00180a018
更新日期:1994-04-12 00:00:00
abstract::G proteins play an important role in transmitting hormonal signals, and fluorescence techniques would be useful to study their cellular distribution and mechanisms. To prepare active fluorescent G protein Go/Gi or beta gamma subunits were reacted with fluorescein isothiocyanate (FITC) to label the alpha (F-alpha) and ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00060a035
更新日期:1993-03-09 00:00:00
abstract::Interleukin-8 (IL-8), a member of the chemokine superfamily, exists as both monomers and dimers, and mediates its function by binding to neutrophil CXCR1 and CXCR2 receptors that belong to the G protein-coupled receptor class. It is now well established that the monomer functions as a high-affinity ligand, but the bin...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0605944
更新日期:2006-06-27 00:00:00
abstract::Nucleotide excision repair (NER) is a crucial pathway in the maintenance of genome stability requiring at least two dozen proteins. XPA and RPA have essential roles in the damage recognition step of NER. To better understand the mechanism of their interactions with DNA, we utilized equilibrium and stop-flow kinetic ap...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi011041q
更新日期:2002-01-08 00:00:00
abstract::Receptor tyrosine kinase (RTK) activation is associated with modulation of heptahelical receptor-stimulated adenylyl cyclase responses. The mechanisms underlying the RTK-mediated enhancement of adenylyl cyclase function remain unclear. In the present studies, we show that the tyrosine kinase-dependent enhancement of a...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0015818
更新日期:2001-02-13 00:00:00
abstract::N-Ethylmaleimide (NEM), which reacts readily with exposed sulfhydryl groups, has been shown to inhibit the activity of the microtubule (MT) motors kinesin, Ncd, and dynein. Currently, the mechanism of inhibition is not known for any of these proteins. To investigate the mechanism by which NEM inhibits Ncd, the recombi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi990706+
更新日期:1999-08-17 00:00:00
abstract::One of the putative proton-transfer pathways leading from solution toward the binuclear center in many cytochrome c oxidases is the D-pathway, so-called because it starts with a highly conserved aspartate [D(I-132)] residue. Another highly conserved amino acid residue in this pathway, glutamate(I-286), has been indica...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0012641
更新日期:2000-12-26 00:00:00
abstract::All phosphagen kinases contain a conserved cysteine residue which has been shown by crystallographic studies, on both creatine kinase and arginine kinase, to be located in the active site. There are conflicting reports as to whether this cysteine is essential for catalysis. In this study we have used site-directed mut...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi011208f
更新日期:2001-10-02 00:00:00
abstract::The sialic acid binding lectin, limulin, was isolated by gel filtration and ion-exchange chromatography from the hemolymph of Limulus polyphemus. When the purified protein was characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the presence of beta-mercaptoethanol, two major protein bands wer...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00638a026
更新日期:1977-09-20 00:00:00