Abstract:
:In protein, conformational changes are often crucial for function but not easy to observe. Two functionally relevant conformational intermediate states of photosynthetic reaction center protein (RCs) are trapped and characterized at low temperature. RCs frozen in the dark do not allow electron transfer from the reduced primary quinone, Q(A)(-), to the secondary quinone, Q(B). In contrast, RCs frozen under illumination in the product (P(+)Q(A)Q(B)(-)) state, with the oxidized electron donor, P(+), and reduced Q(B)(-), return to the ground state at cryogenic temperature in a conformation that allows a high yield of Q(B) reduction. Thus, RCs frozen under illumination are found to be trapped above the ground state in a conformation that allows product formation. When the temperature is raised above 120 K, the protein relaxes to an inactive conformation which is different from the RCs frozen in the dark. The activation energy for this change is 87 +/- 8 meV, and the active and inactive states differ in energy by only 16 +/- 3 meV. Thus, there are several conformational substates along the reaction coordinate with different transition temperatures. The ground state spectra of the RCs in active and inactive conformations report differences in the intraprotein electrostatic field, demonstrating that the dipole or charge distribution has changed. In addition, the electrochromic shift associated with the Q(A)(-) to Q(B) electron transfer at low temperature was characterized. The electron-transfer rate from Q(B)(-) to P(+) was measured at cryogenic temperature and is similar to the rate at room temperature, as expected for an exothermic, electron tunneling reaction in RCs.
journal_name
Biochemistryjournal_title
Biochemistryauthors
Xu Q,Gunner MRdoi
10.1021/bi002326qsubject
Has Abstractpub_date
2001-03-13 00:00:00pages
3232-41issue
10eissn
0006-2960issn
1520-4995pii
bi002326qjournal_volume
40pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract::The concept of using a dynamic base-pairing nucleobase as a mode for degenerate recognition presents a unique challenge to analysis of DNA structure. Proton and phosphorus NMR studies are reported for two nine-residue DNA oligodeoxyribonucleotides, d(CATGGGTAC).d(GTACNCATG) (1) and d(CATGTGTAC).(GTACNCATG) (2), which ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi001448f
更新日期:2001-02-13 00:00:00
abstract::The accessibility of the asparagine-linked carbohydrate chains of human thyrotropin (hTSH) and free alpha and beta subunits was investigated by their susceptibility to endoglycosidases H and F as well as to peptide:N-glycosidase F. Iodinated hTSH or subunits were incubated with a commercial enzyme preparation containi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00392a040
更新日期:1987-09-08 00:00:00
abstract::The kcat and Km values for the bovine heart low molecular weight phosphotyrosyl protein phosphatase catalyzed hydrolysis of 16 aryl phosphate monoesters and of five alkyl phosphate monoesters having the structure Ar(CH2)nOPO3H2 (n = 1-5) were measured at pH 5.0 and 37 degrees C. With the exception of alpha-naphthyl ph...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00101a006
更新日期:1991-09-17 00:00:00
abstract::The cytokine hormone interleukin-2 (IL-2) contains a highly adaptive region that binds small, druglike molecules. The binding properties of this adaptive region have been explored using a "tethering" method that relies on the formation of a disulfide bond between the protein and small-molecule ligands. Using tethering...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi034138g
更新日期:2003-06-03 00:00:00
abstract::We have examined the C cluster in type II CO dehydrogenase (CODH) from Carboxydothermus hydrogenformans using Ni K-edge X-ray absorption near edge spectroscopy and extended X-ray absorption fine structure (EXAFS) spectroscopy. The enzyme was studied under three conditions: "as-isolated" and after treatment with CO or ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi036104e
更新日期:2004-07-20 00:00:00
abstract::Comparative mutagenesis studies of N-(2'-deoxyguanosin-8-yl)-2-acetylaminofluorene (dG-AAF) and N-(2'-deoxyguanosin-8-yl)-2-aminofluorene (dG-AF) adducts positioned in the Nar I restriction enzyme site were performed using Escherichia coli (E. coli) and simian kidney (COS-7) cells. Oligodeoxynucleotides ((5)(')TCCTCG(...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0202878
更新日期:2002-12-03 00:00:00
abstract::Nuclear magnetic resonance (NMR) (15)N relaxation methods have been used to characterize the backbone dynamics of the N-terminal core domain of the HIV-1 capsid protein (CA(151)). The domain, which has an unusually flat, triangular shape, tumbles in solution at 28 degrees C with an effective rotational correlation tim...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi990991x
更新日期:1999-08-10 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::We have developed a panel of antibodies specific for the alpha 1, alpha 2, alpha 3, and beta subunits of the rat Na,K-ATPase. TrpE-alpha subunit isoform fusion proteins were used to generate three antisera, each of which reacted specifically with a distinct alpha subunit isotype. Western blot analysis of rat tissue mi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00437a002
更新日期:1989-05-30 00:00:00
abstract::The active-site zinc in human glutathione-dependent formaldehyde dehydrogenase (FDH) undergoes coenzyme-induced displacement and transient coordination to a highly conserved glutamate residue (Glu-67) during the catalytic cycle. The role of this transient coordination of the active-site zinc to Glu-67 in the FDH catal...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi052554q
更新日期:2006-04-18 00:00:00
abstract::A 600 MHz 1H NMR study of toxin OSK1, blocker of small-conductance Ca2+-activated K+ channels, is presented. The unambiguous sequential assignment of all the protons of the toxin was obtained using TOCSY, DQF-COSY, and NOESY experiments at pH 3.0 (10, 30, and 45 degrees C) in aqueous solution. 3J(N alpha), 3J(alphabet...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9614390
更新日期:1997-02-11 00:00:00
abstract::Treatment of ADP-glucose pyrophosphorylase (EC 2.7.7.27) from the cyanobacterium Anabaena PCC 7120 with phenylglyoxal in 50 mM Hepes, pH 8.0, at 25 degrees C resulted in a time- and concentration-dependent loss of enzyme activity. Phosphate, the inhibitor, protected the enzyme from inactivation most effectively, while...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi9713355
更新日期:1997-10-21 00:00:00
abstract::Adeno-associated virus (AAV) nonstructural proteins Rep78 and Rep68 carry out all DNA transactions that regulate the AAV life cycle. They share two multifunctional domains: an N-terminal origin binding/nicking domain (OBD) from the HUH superfamily and a SF3 helicase domain. A short linker of ∼20 amino acids that is cr...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.5b00610
更新日期:2015-09-29 00:00:00
abstract::The gene coding for the enzyme 2,3-dihydroxybenzoate-AMP ligase (2,3DHB-AMP ligase), responsible for activating 2,3-dihydroxybenzoic acid in the biosynthesis of the siderophore enterobactin, has been subcloned into the multicopy plasmid pKK223-3 and overproduced in a strain of Escherichia coli. The protein is an alpha...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00443a008
更新日期:1989-08-22 00:00:00
abstract::Hexose-1-phosphate uridylyltransferase catalyzes the interconversion of UDP-galactose and glucose-1-P with UDP-glucose and galactose-1-P by a double-displacement mechanism through a covalent intermediate (E-UMP), in which UMP is bonded to one of two histidine residues at the active site, H164 or H166. To identify whic...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00499a003
更新日期:1990-11-27 00:00:00
abstract::The temperature dependence of the 31P NMR spectra of yeast phenylalanine tRNA, E. coli tyrosine, glutamate (2), and formylmethionine tRNA is presented. The major difference between the 31P NMR spectra of the different acceptor tRNAs is in the main cluster region between -0.5 and -1.3 ppm. This confirms an earlier assi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00266a018
更新日期:1982-11-09 00:00:00
abstract::A time-resolved microscope fluorimeter based on a synchroscan streak camera and a fast pulsed laser system has been developed to measure the fluorescence lifetime decay under the fluorescence microscope. This system allows one to measure the nanosecond fluorescence lifetimes of fluorophores in a small spot (0.8-6.3 mi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00240a024
更新日期:1991-07-02 00:00:00
abstract::We have developed a system for targeting foreign DNA to hepatocytes in vitro using a soluble DNA carrier that takes advantage of receptor-mediated endocytosis to achieve internalization. The idea is based on the fact that hepatocytes possess a unique receptor that binds and internalizes galactose-terminal (asialo)glyc...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00403a008
更新日期:1988-02-09 00:00:00
abstract::Taurine/alpha-ketoglutarate (alphaKG) dioxygenase (TauD), an archetype alphaKG-dependent hydroxylase, is a non-heme mononuclear Fe(II) enzyme that couples the oxidative decarboxylation of alphaKG with the conversion of taurine to aminoacetaldehyde and sulfite. The crystal structure of taurine-alphaKG-Fe(II)TauD is kno...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi048746n
更新日期:2005-03-15 00:00:00
abstract::A 37 kDa protein that binds to diadenosine tetraphosphate (Ap4A) was purified from human HeLa cells and identified as uracil DNA glycosylase/glyceraldehyde-3-phosphate dehydrogenase (UDG/GAPDH). Utilizing photoaffinity labeling with [alpha-32P]8N3-Ap4A, an Ap4A binding protein of 37 kDa was identified from HeLa cell n...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00030a007
更新日期:1995-08-01 00:00:00
abstract::Reduced intracellular drug accumulation due to the activity of the drug efflux pump ABC (B1) is a major mechanism in the resistance of cancer cells to chemotherapy. ABC (B1) is a poly specific transporter, and the molecular mechanism of its complex translocation process remains to be elucidated. To understand the proc...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi7023089
更新日期:2008-03-25 00:00:00
abstract::The binding to rat brain synaptosomes of a beta-scorpion toxin, i.e., toxin II of Centruroides suffusus suffusus (Css II), was studied as a function of pH, temperature, and concentration of some monovalent and divalent cations. At 10 degrees C and pH 6.0, the specific binding of 125I-labeled Css II corresponds to a si...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00301a018
更新日期:1984-03-13 00:00:00
abstract::Thiazolinyl imine reductases catalyze the NADPH-dependent reduction of a thiazoline to a thiazolidine, a required step in the formation of the siderophores yersiniabactin (Yersinia spp.) and pyochelin (Pseudomonas aeruginosa). These stand-alone nonribosomal peptide tailoring domains are structural homologues of sugar ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/acs.biochem.6b00735
更新日期:2016-09-27 00:00:00
abstract::We have used limited proteolysis of affinity-labeled estrogen receptors (ER), coupled with antireceptor antibody immunoreactivity, to assess structural features of ER and the relatedness of ER from MCF-7 human breast cancer and rat uterine cells. MCF-7 ER preparations covalently labeled with [3H]tamoxifen aziridine [(...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00382a043
更新日期:1987-04-21 00:00:00
abstract::The mitochondrial folate transporter (MFT) was previously identified in human and hamster cells. Sequence homology of this protein with the inner mitochondrial membrane transporters suggested a domain structure in which the N- and C-termini of the protein are located on the mitochondrial intermembrane-facing surface, ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi062191+
更新日期:2007-02-13 00:00:00
abstract::A likely entry/exit path for nitrogenase substrates, products, and/or protons involves residues α277(Arg), α192(Ser), and α356(Gly), all of which are highly conserved among MoFe proteins from different organisms. The α192(Ser) and α277(Arg) residues form part of a hydrogen-bonded network that also involves α195(His), ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi500546k
更新日期:2014-10-07 00:00:00
abstract::Endoglucanase Cel6A from Thermobifida fusca hydrolyzes the beta-1,4 linkages in cellulose at accessible points along the polymer. The structure of the catalytic domain of Cel6A from T. fusca in complex with a nonhydrolysable substrate analogue that acts as an inhibitor, methylcellobiosyl-4-thio-beta-cellobioside (Glc(...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi0506730
更新日期:2005-10-04 00:00:00
abstract::CNAD (5-beta-D-ribofuranosylnicotinamide adenine dinucleotide) is an isosteric C-glycosidic analogue of NAD(H) containing a neutral pyridine ring. CPAD (5-beta-D-ribofuranosylpicolinamide adenine dinucleotide) is a closely related pyridine-containing analogue with the pyridine nitrogen on the opposite side of the ring...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00205a009
更新日期:1994-10-04 00:00:00
abstract::The crystal structure of ferredoxin-NADP+ reductase (FNR) suggests that Ser96 is directly involved in hydride transfer between the isoalloxazine moiety of FAD and the nicotinamide ring of NADP(H). To probe its role, Ser96 has been mutated to valine (S96V) and glycine (S96G). These mutations primarily affected the inte...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00026a019
更新日期:1995-07-04 00:00:00
abstract::The interaction of the 20-kDa pore-forming domain of colicin A with phospholipid vesicles was investigated by gel permeation chromatography, analytical centrifugation, and electron microscopy. Under the experimental conditions of this study, this peptide was found to interact only with vesicles containing negatively c...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00445a029
更新日期:1989-09-19 00:00:00