Abstract:
:The effect of anions on the stability of different functional conformations of Hb is examined through the determination of the dependence of O(2) affinity on water activity (a(w)). The control of a(w) is effected by varying the sucrose osmolal concentration in the bathing solution according to the "osmotic stress" method. Thus, the hydration change following Hb oxygenation is determined as a function of Cl(-) and of DPG concentration. We find that only approximately 25 additional water molecules bind to human Hb during the deoxy-to-oxy conformation transition in the absence of anions, in contrast with approximately 72 that bind in the presence of more than 50 mM Cl(-) or more than 15 microM DPG. We demonstrate that the increase in the hydration change linked with oxygenation is coupled with anion binding to the deoxy-Hb. Hence, we propose that the deoxy-Hb coexists in two allosteric conformations which depend on whether anion is bound or not: the tense T-state, with low oxygen affinity and anion bound, or a new allosteric P-state, with intermediate oxygen affinity and free of bound anions. The intrinsic oxygen affinity of this unforeseen P-state and the differential binding of Cl(-), DPG, and H(2)O between states P and T and P and R are characteristics which are consistent with those expected for a putative intermediate allosteric state of Hb. These findings represent a new opportunity to explore the structure-function relationships of hemoglobin regulation.
journal_name
Biochemistryjournal_title
Biochemistryauthors
Colombo MF,Seixas FAdoi
10.1021/bi9905361subject
Has Abstractpub_date
1999-09-07 00:00:00pages
11741-8issue
36eissn
0006-2960issn
1520-4995pii
bi9905361journal_volume
38pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract::αB-Crystallin is a chaperone and an anti-apoptotic protein that is strongly expressed in many tissues, including the lens, retina, heart, and kidney. In the human lens, several lysine residues in αB-crystallin are acetylated. We have previously shown that such acetylation is predominant at lysine 92 (K92) and lysine 1...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi400638s
更新日期:2013-11-12 00:00:00
abstract::The solution structure of the C-terminal fragment 255-316 of thermolysin has been determined by two-dimensional proton NMR methods. For this disulfide-free fragment there was a previous proposal according to which it would fold into a stable helical structure forming a dimer at concentrations above 0.06 mM. A complete...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00253a023
更新日期:1994-12-13 00:00:00
abstract::Kinetic and structural data are presented on the interaction with Torpedo californica acetylcholinesterase (TcAChE) of (+)-huperzine A, a synthetic enantiomer of the anti-Alzheimer drug, (-)-huperzine A, and of its natural homologue (-)-huperzine B. (+)-Huperzine A and (-)-huperzine B bind to the enzyme with dissociat...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi020151+
更新日期:2002-09-03 00:00:00
abstract::DNA damage may alter the outcome of protein-nucleic acid interactions. The malondialdehyde-deoxyguanosine adduct, 3-(2'-deoxy-beta-d-erythro-pentofuranosyl)pyrimido[1,2-alpha]purin-10-(3H)-one (M(1)dG), miscodes in vivo and in vitro. M(1)dG is an exocyclic adduct that undergoes ring-opening in duplex DNA to form the a...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0472898
更新日期:2005-04-05 00:00:00
abstract::The pathological prion protein PrP(Sc) is the only known component of the infectious prion. In cells infected with prions, PrP(Sc) is formed posttranslationally by the refolding of the benign cell surface glycoprotein PrP(C) into an aberrant conformation. The two PrP isoforms possess very different properties, as PrP(...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi025958g
更新日期:2002-10-22 00:00:00
abstract::Integrins are one of the major mediators of cellular adherence. Structurally the component alpha and beta chains are characterized by extensive intrachain disulfide bonding. The assignment of these bonds is currently based on homology with the chains of the integrin alphaIIbbeta3. However, recent crystallographic anal...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi034726u
更新日期:2003-11-11 00:00:00
abstract::The interactions of Hoechst 33377 (H1) with 20 different oligomeric duplexes have been investigated via spectrofluorometric titrations and/or thermal denaturation experiments. H1 is shown to form 2:1 complexes with dsDNA binding sites of at least four contiguous A/T base pairs. H1 is also shown to possess the rare abi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0103415
更新日期:2001-05-29 00:00:00
abstract::The metabolism of iron-sulfur ([Fe-S]) clusters requires a complex set of machinery that is still being defined. Mutants of Salmonella enterica lacking apbC have nutritional and biochemical properties indicative of defects in [Fe-S] cluster metabolism. ApbC is a 40.8 kDa homodimeric ATPase and as purified contains lit...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi800551y
更新日期:2008-08-05 00:00:00
abstract::Much interest has centered on two surface loops in the motor domain to explain the differences in enzymatic and mechanical properties of myosin isoforms. We showed that two invariant lysines at the C-terminal end of loop 2, which is part of the actin-binding interface, are required to obtain actin activation [Joel et ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi034415j
更新日期:2003-08-05 00:00:00
abstract::The slowly hydrolyzed ATP analog adenosine 5'-(gamma-thiotriphosphate) (ATP gamma S) has been used in many studies of the muscle motor protein myosin in order to form a stable "weak binding" state analogous to the actin-S1-ATP complex However, the results from studies using ATP gamma S do not always agree with the res...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00049a018
更新日期:1995-12-12 00:00:00
abstract::The molecular mechanism of O2 binding to hemoglobin (Hb) and myoglobin (Mb) is a long-standing issue in the field of bioinorganic and biophysical chemistry. The nature of Fe-O2 bond in oxy Hb and Mb had been extensively investigated by resonance Raman spectroscopy, which assigned the Fe-O2 stretching bands at ∼570 cm-...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.8b00829
更新日期:2018-12-04 00:00:00
abstract::The effects of site-directed mutagenesis were used to explore the role of residues in M4 on the apparent Ki of a selective, K+-competitive inhibitor of the gastric H+,K+ ATPase, SCH28080. A double transfection expression system is described, utilizing HEK293 cells and separate plasmids encoding the alpha and beta subu...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi991837d
更新日期:2000-03-21 00:00:00
abstract::We have labeled the primer binding domain of murine leukemia virus reverse transcriptase (MuLV RT) by covalently cross-linking 5' end labeled d(T)8 to MuLV RT, using ultraviolet light energy. The specificity and the functional significance of the primer cross-linking reaction were demonstrated by the fact that (i) oth...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00240a014
更新日期:1991-07-02 00:00:00
abstract::The calcitonin/CGRP gene pre-mRNA is alternatively spliced in a tissue-specific manner resulting in the formation of calcitonin mRNA in thyroid C-cells and CGRP mRNA in neurons. Computer analysis of the RNA containing the 3' splice acceptor of the calcitonin-specific exon 4 predicts that this region has the potential ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9808058
更新日期:1998-11-10 00:00:00
abstract::High hydrostatic pressure has been shown to cause reversible dissociation of the isolated apo beta 2 dimer of tryptophan synthase from Escherichia coli into enzymatically inactive monomers [Seifert, T., Bartholmes, P., & Jaenicke, R. (1982) Biophys. Chem. 15, 1-8]. Addition of the coenzyme pyridoxal 5'-phosphate affec...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00323a016
更新日期:1985-01-15 00:00:00
abstract::We have characterized by EPR the interaction of the Em,7 = -50 mV [4Fe-4S] cluster of Escherichia coli DMSO reductase (DmsABC) with a menaquinol (MQH2) binding site. Potentiometric titrations indicate that in DmsAB(C102S)C, the Em,7 = -50 mV [4Fe-4S] cluster is replaced by an Em,7 = +260 mV [3Fe-4S] cluster. The Q-poo...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi951584y
更新日期:1996-03-12 00:00:00
abstract::The Fo membrane domain of the F1Fo-ATP synthase complex has been purified from bovine heart mitochondria. The purification procedure involves the removal of peripheral membrane proteins, including F1-ATPase, from submitochondrial particles with guanidine hydrochloride, followed by extraction of Fo and other membrane p...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00191a026
更新日期:1994-06-28 00:00:00
abstract::Pterin-free inducible nitric oxide synthase (iNOS) was reconstituted with tetrahydrobiopterin (H(4)B) or tetrahydrobiopterin analogues (5-methyl-H(4)B and 4-amino-H(4)B), and the ability of bound 5-methyl-H(4)B and 4-amino-H(4)B to support catalysis by either full-length iNOS (FLiNOS) or the isolated heme domain (HDiN...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi035491p
更新日期:2003-11-18 00:00:00
abstract::The role of histidine in catalysis by prostaglandin H synthase has been investigated using chemical modification with diethyl pyrocarbonate (DEPC), an agent that has been found to rather selectively derivatize histidine residues in proteins under mild conditions. Incubation of the synthase apoprotein with DEPC at pH 7...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00124a013
更新日期:1992-03-10 00:00:00
abstract::Sensory rhodopsin II (SRII) is unique among the archaeal rhodopsins in having an absorption maximum near 500 nm, blue shifted roughly 70 nm from the other pigments. In addition, SRII displays vibronic structure in the lambda(max) absorption band, whereas the other pigments display fully broadened band maxima. The mole...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0116487
更新日期:2001-11-20 00:00:00
abstract::The peptide alpha 1(III)-CB9 was prepared and purified from human liver, and its amino acid sequence was determined. Automated Edman degradation of the intact peptide and peptides derived from selective cleavage with hydroxylamine and digestions with trypsin, thermolysin, and Staph V8 protease enabled determination of...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00512a040
更新日期:1981-04-28 00:00:00
abstract::To better understand how amino acid sequences specify unique tertiary folds, we have used random mutagenesis and phage display selection to evolve proteins with a high degree of sequence identity but different tertiary structures (homologous heteromorphs). The starting proteins in this evolutionary process were the Ig...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi051231r
更新日期:2005-11-01 00:00:00
abstract::Protein folding in vivo takes place in a highly crowded environment. The resulting excluded volume forces are thought to stabilize folded forms of proteins. In agreement, many in vitro studies have shown that the presence of macromolecular crowding agents increases the stability of folded proteins but often by only a ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi500222g
更新日期:2014-04-15 00:00:00
abstract::IFABP is a small beta-barrel protein with a short helix-turn-helix motif near the N-terminus that is thought to participate in the regulation of the uptake and delivery of fatty acids. In a previous work, we detected by near UV circular dichroism a reversible conformational transition of this protein occurring between...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi020680d
更新日期:2003-06-24 00:00:00
abstract::Tritiated sodium borohydride was used to reduce the substrates of triosephosphate isomerase in the presence of the enzyme, and the mixture of the four possible products (D-[1(R)-3H]; D-[1(S)-3H]-; D-[2-3H]-, and L-[2-3H]glycerol 3-phosphate) was analyzed. While enzyme-bound dihydroxyacetone phosphate is reduced comple...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00692a020
更新日期:1975-10-21 00:00:00
abstract::Absorbance difference spectra were recorded at 20 degrees C from 30 ns to milliseconds after photolysis of lauryl maltoside suspensions of artificial visual pigments derived from 9-cis isomers of 5-ethylretinal, 8,16-methanoretinal (a 6-s-trans-bicyclic analogue), or 5-demethyl-8-methylretinal. In all three pigments, ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi011461f
更新日期:2002-02-12 00:00:00
abstract::The catalytic mechanism of valyl-tRNA synthetase from baker's yeast has been investigated by pre-steady-state and steady-state kinetic measurements and end product dissociation studies. The pre-steady-state kinetics show a lag period during the early time when the reaction is started with free enzyme. The preincubatio...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00511a001
更新日期:1981-04-14 00:00:00
abstract::Shaker potassium (K+) channels normally lack intrasubunit and intersubunit disulfide bonds. However, disulfide bonds are formed between Shaker subunits in intact cells exposed to oxidizing conditions. Upon electrophoresis under nonreducing conditions, intersubunit disulfide bond formation was detected by the presence ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi961083s
更新日期:1996-09-17 00:00:00
abstract::The method of transient electric birefringence has been applied to study the conformation of protein-sodium dodecyl sulfate complexes. A model of a deformable prolate ellipsoid has been proposed for the protein-dodecyl sulfate complex. This model is compared to the models proposed by J. A. Reynolds and C. Tanford (197...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00685a030
更新日期:1975-07-15 00:00:00
abstract::Manganese peroxidase (MnP) from Phanerochaete chrysosporium undergoes a pH-dependent conformational change evidenced by changes in the electronic absorption spectrum. This high- to low-spin alkaline transition occurs at approximately 2 pH units lower in an F190I mutant MnP when compared to the wild-type enzyme. Herein...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi000679j
更新日期:2000-08-15 00:00:00