Abstract:
:We report the use of electrospray ionization (ESI) mass spectrometry (MS) in conjunction with online rapid mixing to monitor the kinetics of acid-induced ferrihemoglobin denaturation. Under equilibrium conditions, the hemoglobin mass spectrum is dominated by the intact heterotetramer. Dimeric and monomeric species are also observed at lower intensities. In addition, ionic signals corresponding to hexameric (tetramer-dimer) and octameric (tetramer x 2) hemoglobin species are observed. These complexes may represent weak solution-phase assemblies. The acid-induced denaturation process was monitored for reaction time ranging from 9 ms to approximately 3 s. The data obtained were subjected to a global analysis procedure which simultaneously fit all kinetic (ESI-MS intensity vs time) profiles to multiexponential expressions. Results of the global analysis are consistent with the coexistence of two subpopulations of tetrameric hemoglobin which differ in their disassembly rates and ESI charge states. The higher-charge state tetramer ions preferentially dissociate via a rapid pathway (tau(1) = 51 ms), resulting in the transient formation of a heme-saturated dimer, holo-alpha-globin, and a heme-deficient dimer. The latter is shown by MS/MS to be comprised of a heme-bound alpha-subunit complexed with an apo-beta-chain. The slow-decaying tetramer population, apparent at a slightly lower average charge state, breaks down into its monomeric constituents with no observable intermediate species (tau(2) = 390 ms). Surprisingly, unfolded apo-alpha-globin is formed more rapidly than unfolded apo-beta-globin. The appearance of the latter occurs with a relaxation time tau(3) of 1.2 s. It is postulated that accumulation of unfolded apo-beta-globin is delayed by transient population of an undetected unfolding intermediate.
journal_name
Biochemistryjournal_title
Biochemistryauthors
Simmons DA,Wilson DJ,Lajoie GA,Doherty-Kirby A,Konermann Ldoi
10.1021/bi048501asubject
Has Abstractpub_date
2004-11-23 00:00:00pages
14792-801issue
46eissn
0006-2960issn
1520-4995journal_volume
43pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract::In order to clarify the functional and structural role of intra- and intersubunit hydrogen bonds in human hemoglobin (Hb A), we prepared two artificial beta chain mutant hemoglobins by site-directed mutagenesis. The mutant Hb Phe-37 beta, in which Trp-37 beta is replaced by Phe to remove the intersubunit hydrogen bond...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00127a030
更新日期:1992-03-31 00:00:00
abstract::From an evolutionary point of view, plant and animal ferritins arose from a common ancestor, but plant ferritin exhibits different features as compared with the animal analogue. One major difference is that the 4-fold channels naturally occurring in plant ferritin are hydrophilic, whereas the 4-fold channels in animal...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi500066m
更新日期:2014-04-15 00:00:00
abstract::To better understand origin recognition and initiation of DNA replication, we have examined by NMR complexes formed between the origin-binding domain of SV40 T antigen (T-ag-obd), the initiator protein of the SV40 virus, and cognate and noncognate DNA oligomers. The results reveal two structural effects associated wit...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi030228+
更新日期:2004-06-08 00:00:00
abstract::Lateral mobilities of fluorescent cell surface probes have been measured on normal (3T3) and transformed (SV3T3) cultured mouse fibroblasts. There is little discernible difference in the mobilities of a lipid analogue (diI), a fluorescent ganglioside derivative (GM1), and tetramethylrhodamine-labeled succinylated conc...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00551a011
更新日期:1980-05-13 00:00:00
abstract::ISU-type proteins mediate cluster transfer to apo protein targets. Rate constants have been determined for cluster transfer from ISU to apo Fd for both Homo sapiens and Schizosaccharomyces pombe proteins, and cross reactions have also been examined. Substitution of a key aspartate residue of ISU is found to decrease t...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0256781
更新日期:2002-07-16 00:00:00
abstract::The unfolding of human plasma alpha 1-acid glycoprotein (AGP) induced by heat or guanidine hydrochloride was studied under equilibrium conditions. In thermal unfolding, an intermediate state was detected by the appearance of unusual positive difference absorption bands in the 287-295-nm region, which occurred at lower...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00489a026
更新日期:1990-09-18 00:00:00
abstract::Conformational distributions of a four-way DNA junction have been examined by time-resolved fluorescence resonance energy transfer (FRET). A series of dye-labeled junctions were synthesized with donor (fluorescein) and acceptor (tetramethylrhodamine) dyes conjugated to the 5' termini of the duplex arms in all six pair...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00213a014
更新日期:1993-12-21 00:00:00
abstract::One cause of multidrug resistance is the overexpression of P-glycoprotein, a 170 kDa plasma membrane ABC transporter, which functions as an ATP-driven efflux pump with broad specificity for hydrophobic drugs, peptides, and natural products. The protein appears to interact with its substrates within the membrane enviro...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0485326
更新日期:2005-01-18 00:00:00
abstract::Low-temperature electronic absorption and room temperature circular dichroism (CD) and magnetic circular dichroism (MCD) spectra are reported for ascorbate oxidase. Bands attributable to d-d electronic transitions in the type 1 (blue) coppers (2B2 ground state) have been observed at 5800, 10000, and 12000 cm-1 (1725, ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00510a044
更新日期:1981-03-31 00:00:00
abstract::Insulin decreases multifunctional protein kinase (MFPK) activity in rat adipose tissue [Ramakrishna, S., & Benjamin, W. B. (1988) J. Biol. Chem. 263, 12677-12681]. Insulin also decreases the phosphorylation of peptide B but increases the phosphorylation of peptide A of ATP-citrate lyase (ATP-CL). The mechanism for thi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00428a067
更新日期:1989-01-24 00:00:00
abstract::Both agonist- and antagonist-bound glucocorticoid receptors (GRs) and progesterone receptors (PRs) regulate gene transcription with the assistance of corepressors (NCoR and SMRT) and coactivators (TIF2/GRIP1, SRC1, and AIB1). Receptor binding of these cofactors is competitive and is considered to involve interactions ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi7004575
更新日期:2007-07-10 00:00:00
abstract::The 270-MHz 1H nuclear magnetic resonance spectra of the apo, copper(I)-zinc(II), and copper(II)-zinc(II) forms of bovine erythrocyte superoxide dismutase (EC 1.15.1.1) are reported, and assignments of resonances to ten amino acid residues are proposed. The data require that at least four and probably six histidine re...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00633a003
更新日期:1977-07-12 00:00:00
abstract::A new strategy to form stable and sequence-specific triple helical DNA structures at mixed purine/pyrimidine sequences using a combination of four C-glycosides (TRIPsides) has been described [Li et al. (2003) J. Am. Chem. Soc. 125, 2084]. The partial realization of the approach is demonstrated by incorporating two of ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi035648d
更新日期:2004-02-17 00:00:00
abstract::In an effort to characterize the bimolecular interface between parathyroid hormone (PTH) and its human receptor PTH1-Rc (hPTH1-Rc), we previously identified two contact sites in the receptor: one for position 1 and another for position 13 (located at the ends of the principal activation domain) in PTH(1-34). The prese...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi000195n
更新日期:2000-07-18 00:00:00
abstract::The central importance of chorismate enzymes in bacteria, fungi, parasites, and plants combined with their absence in mammals makes them attractive targets for antimicrobials and herbicides. Two of these enzymes, anthranilate synthase (AS) and aminodeoxychorismate synthase (ADCS), are structurally and mechanistically ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.5b00013
更新日期:2015-04-14 00:00:00
abstract::Overall activation volumes for multistep reactions are not usually pressure independent. The present investigation gives a quantitative description of this effect under Theory. Simple relations are obtained which can easily be applied to experimental data and which allow more insight into the dynamics of enzyme reacti...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00405a024
更新日期:1988-03-08 00:00:00
abstract::In this work we modeled the circular dichroism (CD) spectrum of LHCII, the main light harvesting antenna of photosystem II of higher plants. Excitonic calculations are performed for a monomeric subunit, taken from the crystal structure of trimeric LHCII from spinach [Liu, Z. F., Yan, H. C., Wang, K. B., Kuang, T. Y., ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi062031y
更新日期:2007-04-24 00:00:00
abstract::Carboxymethylation with 14 C-labeled iodoacetate of cysteine residues in wild-type beta-galactosidase from Escherichia coli and in a defective beta-galactosidase from deletion mutant strain M15 was investigated in order to determine accessible positions in the tetrameric wild-type form and the dimeric mutant M15 prote...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00617a015
更新日期:1978-11-28 00:00:00
abstract::Dihydrouridine is absent from the tRNA of almost all hyperthermophiles and most Archaea but is ubiquitous in the tRNA of Eubacteria and Eukaryotes. In order to investigate whether this could be due to instability, the rate of ring opening of dihydrouridine was measured between 25 and 120 degrees C. The dihydrouridine ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi951577+
更新日期:1996-01-09 00:00:00
abstract::The acid-induced denaturation of barnase and its mutants has been analyzed to search for partly-folded intermediates. Differential scanning calorimetry of barnase deviates from two-state behavior below pH 4.0 at low ionic strength, with the maximum discrepancy at pH 2.7. Addition of 200 mM KCl apparently restores the ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00203a015
更新日期:1994-09-20 00:00:00
abstract::The following polynucleotides containing the antibiotic tubercidin (Tu; 4-amino-7-beta-D-ribofuranosylpyrrolo-[2,3-d]pyrimidine) were enzymatically synthesized by polymerization of adenosine 5'-diphosphate-tubercidin 5'-diphosphate mixtures with polynucleotide phosphorylase: poly(A2,Tu), poly(A,Tu2), and poly(Tu). The...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00512a030
更新日期:1981-04-28 00:00:00
abstract::High-resolution, solid-state 15N NMR has been used to study the chemical shift anisotropies of the Schiff bases in bacteriorhodopsin (bR) and in an extensive series of model compounds. Using slow-spinning techniques, we are able to obtain sufficient rotational sideband intensity to determine the full 15N chemical shif...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00434a033
更新日期:1989-04-18 00:00:00
abstract::The sigmoidal dependence of activity on substrate concentration exhibited by the regulatory enzyme aspartate transcarbamoylase (ATCase) of Escherichia coli is generally attributed to a ligand-promoted change in the quaternary structure of the enzyme. Although a global conformational change in ATCase upon the binding o...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00467a019
更新日期:1990-04-17 00:00:00
abstract::Cytochrome c-553 from Desulfovibrio vulgaris exhibits a highly exposed heme and an unusually low reduction potential with respect to other c-type cytochromes. Solvent heme exposure has been indicated as one of the most important factors in modulating the midpoint potential of the redox center. To test this hypothesis,...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi025759x
更新日期:2002-07-09 00:00:00
abstract::Inducible dimers are powerful tools for controlling biological processes through colocalizing signaling molecules. To be effective, an inducible system should have a dissociation constant in the "off" state that is greater (i.e., weaker affinity) than the concentrations of the molecules that are being controlled, and ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.6b00529
更新日期:2016-09-20 00:00:00
abstract::The reactions of metmyoglobin (metMb) and methemoglobin (metHb), oxidized to their respective oxoferryl free radical species (.Mb-FeIV = O/.Hb-4FeIV = O) by tert-butyl hydroperoxide (t-BuOOH), with nitric oxide (NO.) were studied by a combination of optical, electron spin resonance (ESR), ionspray mass (MS), fluoresce...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00020a014
更新日期:1995-05-23 00:00:00
abstract::The molecule 3',6'-bis(4-guanidinobenzoyloxy)-5-[N'-(4-carboxyphenyl)thioureido[spirop]isobenzofuran-1-(3H),9'-[9H]xanthen]-3-one, abbreviated FDE, was designed and synthesized as a fluorogenic active-site titrant for serine proteases. It is an analogue of p-nitrophenyl p-guanidino-benzoate (NPGB) in which a fluoresce...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00518a010
更新日期:1981-07-21 00:00:00
abstract::The three-dimensional high-resolution structure of rhodopsin is unknown, as is the case for almost all integral membrane patients. As part of an alternative approach to determine of membrane protein structure, we are pursuing the structure of cytoplasmic domains of this G-protein receptor. A peptide, rhoIII, with the ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00045a002
更新日期:1995-11-14 00:00:00
abstract::Protein amyloid fibrils are originally identified as pathological entities in a variety of neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. Recent studies have revealed that amyloid fibrils also serve as functional protein assemblies to fulfill a wide range of biological functions. Decip...
journal_title:Biochemistry
pub_type: 杂志文章,评审
doi:10.1021/acs.biochem.9b01069
更新日期:2020-02-11 00:00:00
abstract::The membrane topology of the human apical sodium-dependent bile acid transporter (hASBT) remains unresolved. Whereas N-glycosylation analysis favors a 7 transmembrane (TM) model, membrane insertion scanning supports a 9TM topology. In order to resolve this controversy, we used dual label epitope insertion to systemati...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi052202j
更新日期:2006-01-24 00:00:00