Abstract:
:The hydration of CO2 catalyzed by carbonic anhydrase requires proton transfer from the zinc-bound water at the active site to solution for each cycle of catalysis. In the most efficient of the mammalian carbonic anhydrases, isozyme II, this transfer is facilitated by a proton shuttle residue, His 64. Murine carbonic anhydrase V (mCA V) has a sterically constrained tyrosine at the analogous position; it is not an effective proton shuttle, yet catalysis by this isozyme still achieves a maximal turnover in CO2 hydration of 3 x 10(5) s-1 at pH > 9. We have investigated the source of proton transfer in a truncated form of mCA V and identified several basic residues, including Lys 91 and Tyr 131, located near the mouth of the active-site cavity that contribute to proton transfer. Intramolecular proton-transfer rates between these shuttle groups and the zinc-bound water were estimated as the rate-determining step in kcat for hydration of CO2 measured by stopped-flow spectrophotometry and in the exchange of 18O between CO2 and water measured by mass spectrometry. Comparison of kcat in catalysis by Lys 91 and Tyr 131 and the corresponding double mutant showed a strong antagonistic interaction between these sites, suggesting a cooperative behavior in facilitating the proton-transfer step of catalysis. Replacing four potential proton shuttle residues produced a multiple mutant that had 10% of the catalytic turnover kcat of the wild type, suggesting that the main proton shuttles have been accounted for in mCA V. These replacements caused relatively small changes in kcat/Km for hydration, which measures the interconversion of CO2 and HCO3- in a stage of catalysis that is separate and distinct from the proton transfers; these measurements serve as a control indicating that the replacements of proton shuttles have not caused structural changes that affect reactivity at the zinc.
journal_name
Biochemistryjournal_title
Biochemistryauthors
Earnhardt JN,Qian M,Tu C,Laipis PJ,Silverman DNdoi
10.1021/bi9729209subject
Has Abstractpub_date
1998-05-19 00:00:00pages
7649-55issue
20eissn
0006-2960issn
1520-4995pii
bi9729209journal_volume
37pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract::The interaction between factor Xa and factor Va was investigated both in solution and in the presence of phospholipid vesicles with varying contents of phosphatidylserine. The binding parameters were inferred from the kinetics of prothrombin activation. Factor Xa and factor Va form in solution an equimolar complex wit...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00265a018
更新日期:1982-10-26 00:00:00
abstract::The temperature dependence of steady-state kinetics has been studied with horse liver alcohol dehydrogenase (HLADH) using protonated and deuterated benzyl alcohol as substrates in methanol/water mixtures between +3 and -50 degrees C. Additionally, the competitive isotope effects, k(H)/k(T) and k(D)/k(T), were measured...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi002075l
更新日期:2001-02-20 00:00:00
abstract::Onconase (ONC) from Rana pipiens is the smallest member of the ribonuclease A (RNase A) superfamily. Despite a tertiary structure similar to RNase A, ONC is distinguished by an extremely high thermodynamic stability. In the present paper we have probed the significance of three structural regions, which exhibit struct...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0525223
更新日期:2006-03-21 00:00:00
abstract::Membrane vesicles from Mycobacterium phlei contain carrier proteins for proline, glutamine, and glutamic acid. The transport of proline is Na+ dependent and required substrate oxidation. A proline carrier protein was solubilized from the membrane vesicles by treatment with cholate and Triton X-100. Electron microscopi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00578a015
更新日期:1979-05-29 00:00:00
abstract::Hydrogen-bonding and ionic interactions play fundamental roles in macromolecular recognition and function. In contrast to lysines and arginines, how histidines mediate these interactions is less well-understood due to the unique properties of its side chain imidazole that include an aromatic ring with two titratable n...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.8b00756
更新日期:2018-10-16 00:00:00
abstract::SH2 domain-containing inositol 5-phosphatases 1 (SHIP1) and 2 (SHIP2) are structurally similar proteins that catalyze the degradation of lipid secondary messenger phosphatidylinositol 3,4,5-triphosphate to produce phosphatidylinositol 3,4-diphosphate. Despite their high sequence identity (51%), SHIP1 and SHIP2 share l...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9012462
更新日期:2009-11-24 00:00:00
abstract::Vanadium(IV) oxo-bis(maltolato) (BMOV), an organovanadium compound, is a potent insulinomimetic agent and improves glucose homeostasis in various models of diabetes. We have shown previously that BMOV stimulates the phosphorylation of PKB which may contribute as one of the mechanisms for the insulinomimetic effect of ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi060403x
更新日期:2006-09-26 00:00:00
abstract::The cytochrome P450-dependent terminal desaturation of valproic acid (VPA) is of both toxicological and mechanistic interest because the product, 4-ene-VPA, is a more potent hepatotoxin than the parent compound and its generation represents a rather novel metabolic reaction for the cytochrome P450 system. In the prese...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00024a013
更新日期:1995-06-20 00:00:00
abstract::A crystal structure of human fibrinogen has been determined at approximately 3.3 A resolution. The protein was purified from human blood plasma, first by a cold ethanol precipitation procedure and then by stepwise chromatography on DEAE-cellulose. A product was obtained that was homogeneous on SDS-polyacrylamide gels....
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi802205g
更新日期:2009-05-12 00:00:00
abstract::Chloride intracellular channel protein 1 (CLIC1) functions as an anion channel in plasma and nuclear membranes when its soluble monomeric form converts to an integral-membrane form. The transmembrane region of CLIC1 is located in its thioredoxin-like domain 1, but the mechanism whereby the protein converts to its memb...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9010607
更新日期:2009-09-08 00:00:00
abstract::The S-adenosylmethionine (SAM) riboswitch is one of the most recurrent riboswitches found in bacteria and has three known different natural aptamers. The Bacillus subtilis yitJ SAM riboswitch aptamer is organized around a four-way junction which is characterized by the presence of a pseudoknot and a K-turn motif. By r...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi701164y
更新日期:2008-02-12 00:00:00
abstract::We use laser flash photolysis and time-resolved Raman spectroscopy of CO-bound H93G myoglobin (Mb) mutants to study the influence of the proximal ligand on the CO rebinding kinetics. In H93G mutants, where the proximal linkage with the protein is eliminated and the heme can bind exogenous ligands (e.g., imidazole, 4-b...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi049077g
更新日期:2004-08-31 00:00:00
abstract::Synaptotagmin I is the calcium sensor in synchronous neurotransmitter release caused by fusion of synaptic vesicles with the presynaptic membrane in neurons. Synaptotagmin I interacts with acidic phospholipids, but also with soluble N-ethylmaleimide-sensitive factor attachment receptors (SNAREs), at various stages in ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi101864k
更新日期:2011-04-05 00:00:00
abstract::The folding kinetics of a 16-residue beta-hairpin (trpzip4) and five mutants were studied by a laser-induced temperature-jump infrared method. Our results indicate that mutations which affect the strength of the hydrophobic cluster lead to a decrease in the thermal stability of the beta-hairpin, as a result of increas...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi052039s
更新日期:2006-02-28 00:00:00
abstract::Cyanobacteriochromes (CBCRs) are photosensory proteins related to the red/far-red phytochromes. Like phytochromes, CBCRs use linear tetrapyrrole (bilin) chromophores covalently attached via a thioether linkage to a conserved Cys residue also found in plant and cyanobacterial phytochromes. Unlike almost all phytochrome...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi300171s
更新日期:2012-05-01 00:00:00
abstract::The cardiac-specific Nkx2.5 homeodomain has been expressed as a 79-residue protein with the oxidizable Cys(56) replaced with Ser. The Nkx2.5 or Nkx2.5(C56S) homeodomain is 73% identical in sequence to and has the same NMR structure as the vnd (ventral nervous system defective)/NK-2 homeodomain of Drosophila when bound...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi050835s
更新日期:2005-09-20 00:00:00
abstract::A conformational change in the DNA plasmid ColE1 appears to occur upon specific binding of the restriction endonuclease EcoRI. Enzyme association alters the chiral discrimination found in binding metallointercalators to DNA sites. The complexes tris(1,10-phenanthroline)ruthenium(II), Ru(phen)3(2+), tris(4,7-diphenyl-1...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00356a053
更新日期:1986-04-22 00:00:00
abstract::The primary electron acceptor pheophytin (Pheo(D1)) plays a crucial role in regulation of forward and backward electron transfer in photosystem II (PSII). It is known that some cyanobacteria control the Pheo(D1) potential in high-light acclimation by exchanging the D1 proteins from different copies of the psbA genes. ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9018829
更新日期:2010-01-26 00:00:00
abstract::The reversible decline of the nicotinic acetylcholine receptor's response to acetylcholine during prolonged exposure to acetylcholine is known as desensitization. Here, we studied ethanol's modulation of fast agonist-induced desensitization of the nicotinic acetylcholine receptor in postsynaptic membrane vesicles from...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00197a009
更新日期:1994-08-09 00:00:00
abstract::The epidermal growth factor receptor (EGFR) kinase is activated by a variety of mutations in human cancers. R776H is one such recurrent mutation (R752H in another numbering system) in the αC-β4 loop of the tyrosine kinase domain that activates EGFR in the absence of the activating EGF ligand. However, the mechanistic ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.5b00444
更新日期:2015-07-14 00:00:00
abstract::We have employed high-performance liquid chromatography (HPLC) to investigate the syntheses of histones H1 and H1o as synchronized cells traverse from mitosis to S phase. Chinese hamster (line CHO) cells were synchronized by mitotic selection, and, at appropriate times, they were pulse labeled for 1 h with [3H]lysine....
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00329a031
更新日期:1985-04-09 00:00:00
abstract::The beta-glucosidase from Agrobacterium sp. catalyzes the hydrolysis of beta-glucosides via a covalent alpha-D-glucopyranosyl-enzyme intermediate involving Glu358. Hydrolysis of 2,4-dinitrophenyl beta-D-glucopyranoside by the low activity Glu358Asp mutant of Agrobacterium beta-glucosidase is accompanied by time-depend...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00044a033
更新日期:1995-11-07 00:00:00
abstract::R67 dihydrofolate reductase (DHFR) is a plasmid-encoded, type II enzyme. Four monomers (78 amino acids long) assemble into a homotetramer possessing 222 symmetry. In previous studies, a tandem array of four R67 DHFR gene copies was fused in frame to generate a functional monomer named Quad1. This protein possessed the...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi1005943
更新日期:2010-08-31 00:00:00
abstract::We have found a new class of inhibitors of the bacterial bioluminescence reaction, the N,N-diphenylalkylamines and acids. We have studied the action of one of these compounds 2,2-diphenylpropylamine. The amine was competitive with the long-chain aliphatic aldehyde substrate (Ki congruent to 0.1 mM) but caused an incre...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00522a027
更新日期:1981-09-15 00:00:00
abstract::The active site structures of human Q31 granzyme A, murine granzymes (A, B, C, D, E, and F), and human granzymes (A, B, and 3) isolated from cytotoxic T lymphocytes (CTL) were studied with peptide thioester substrates, peptide chloromethyl ketone, and isocoumarin inhibitors. Human Q31, murine, and human granzyme A hyd...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00222a027
更新日期:1991-02-26 00:00:00
abstract::The reaction catalyzed by orotidine 5'-monophosphate decarboxylase (OMPDC) is accompanied by exceptional values for rate enhancement (k(cat)/k(non) = 7.1 × 10(16)) and catalytic proficiency [(k(cat)/K(M))/k(non) = 4.8 × 10(22) M(-1)]. Although a stabilized vinyl carbanion/carbene intermediate is located on the reactio...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi2012355
更新日期:2011-10-04 00:00:00
abstract::Myc and Max belong to the b-HLH-LZ family of transcription factors. Heterodimerization between Myc and Max or homodimerization of Max allows these proteins to bind their cognate DNA sequence known as the E-box (CACGTG). Recent evidence has suggested that the c-Myc/Max heterodimeric b-HLH-LZ could interact to form a he...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi700076m
更新日期:2007-09-11 00:00:00
abstract::Chicken nucleoside triphosphate diphosphohydrolase 8 (NTPDase8) is a cell surface ectonucleotidase with a large extracellular domain (ECD) containing the active site and is anchored to the membrane by two transmembrane domains (TMDs) at the N- and C-termini. Unlike other cell surface NTPDases that have been characteri...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi901820c
更新日期:2010-01-12 00:00:00
abstract::Isopentenyl diphosphate:dimethylallyl diphosphate isomerase (EC 5.3.3.2) catalyzes the antarafacial [1.3] allylic rearrangement of isopentenyl diphosphate (IPP) to its electrophilic allylic isomer dimethylallyl diphosphate (DMAPP). Active-site thiols at C138 and C139 were recently identified by covalent modification u...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00180a014
更新日期:1994-04-12 00:00:00
abstract::A fluorescent derivative of lysine-258 isolated from the active site of aspartate aminotransferase modified by treatment of the apoenzyme with pyridoxal 5'-sulfate has been characterized as a substituted 2H-pyrrolo[3,4-c]pyridine. Similar pyrrolopyridines are produced in up to 20% yield by reaction of pyridoxal sulfat...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00264a016
更新日期:1982-10-12 00:00:00