Abstract：
:A single histidine residue has been placed at either the N-terminus or the C-terminus of each of the two alpha-helices of barnase. The pKa of that histidine residue in each of the four mutants has been determined by 1H NMR. The pKas of the two residues at the C-terminus are, on average, 0.5 unit higher, and those of the residues at the N-terminus are 0.8 unit lower, than the pKa of histidines in unfolded barnase at low ionic strength. The conformational stability of the mutant proteins at different values of pH has been measured by urea denaturation. C-Terminal histidine mutants are approximately 0.6 kcal mol-1 more stable when the introduced histidine is protonated, both at low and high ionic strength. N-Terminal mutants with a protonated histidine residue are approximately 1.1 kcal mol-1 less stable at low ionic strength and 0.5 kcal mol-1 less stable at high ionic strength (1 M NaCl). The low-field 1H NMR spectra of the mutant proteins at low pH suggest that the C-terminal histidines form hydrogen bonds with the protein while the N-terminal histidines do not form the same. The perturbations of pKa and stability result from a combination of different electrostatic environments and hydrogen-bonding patterns at either ends of helices. The value of 0.6 kcal mol-1 represents a lower limit to the favorable electrostatic interaction between the alpha-helix dipole and a protonated histidine residue at the C-terminal end of the helix.(ABSTRACT TRUNCATED AT 250 WORDS)
journal_name
Biochemistryjournal_title
Biochemistryauthors
Sancho J,Serrano L,Fersht ARdoi
10.1021/bi00123a006subject
Has Abstractpub_date
1992-03-03 00:00:00pages
2253-8issue
8eissn
0006-2960issn
1520-4995journal_volume
31pub_type
杂志文章相关文献
BIOCHEMISTRY文献大全abstract：:Horse heart cytochrome c has been modified by 8-azido-ATP and the electron-transfer activity of the modified cytochrome c's to bovine heart cytochrome c oxidase (CcO) under physiological ionic strengths has been studied by the laser flash photolysis technique with 5-deazariboflavin and EDTA as the electron donor. The ...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00008a035
更新日期：1995-02-28 00:00:00
abstract：:His12 and His119 are critical for catalysis of RNA cleavage by ribonuclease A (RNase A). Substitution of either residue with an alanine decreases the value of k(cat)/K(M) by more than 10(4)-fold. His12 and His119 are proximal to the scissile phosphoryl group of an RNA substrate in enzyme-substrate complexes. Here, the...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi0100182
更新日期：2001-04-24 00:00:00
abstract：:This paper provides further characterization of a receptor that, in cells lacking the LDL receptor (FH fibroblasts), mediates lipoprotein binding, uptake, and degradation when incubated with oleate at concentrations not exceeding albumin binding capacity. This oleate-activated receptor is genetically distinct from the...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00171a017
更新日期：1994-02-08 00:00:00
abstract：:Comparison of available sequences of HLA-A and HLA-B antigens shows that variable positions are predominantly localized in four segments spanning residues 63-85, 105-116, 138-156, and 177-194. The fourth segment is unique in that it contains no differences between antigens of the same locus. Secondary folding of HLA h...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00300a007
更新日期：1984-02-28 00:00:00
abstract：:The baker's yeast saccharopine dehydrogenase (EC 1.5.1.7) was inactivated by 2,3-butanedione following pseudo-first-order reaction kinetics. The pseudo-first-order rate constant for inactivation was linearly related to the butanedione concentration, and a value of 7.5 M-1 min-1 was obtained for the second-order rate c...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00506a004
更新日期：1981-02-03 00:00:00
abstract：:The N-terminal 17% of apolipoprotein B (apoB-17) is secreted lipid-poor while apoB-41 particles are secreted with a triacylglycerol (TAG)-rich core. Thus, the sequence between apoB-17 and apoB-41 is necessary for the assembly of TAG-rich lipoproteins. To delineate this region, C127 cells were permanently transfected t...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi000791h
更新日期：2000-08-15 00:00:00
abstract：:The effect of araC incorporation into the dodecamer duplex [d(CGCGAATT) (araC)d(GCG)]2 was examined by comparing its nuclear magnetic resonance (NMR)-determined solution structure with that of the control duplex d[(CGCGAATTCGCG)]2. 1H and 31P resonances in both duplexes were assigned using a combination of 2-D 1H NMR ...
journal_title：Biochemistry
pub_type： 杂志文章
doi：
更新日期：1994-09-27 00:00:00
abstract：:Histone redistributions between endogenous DNA in calf thymus chromatin and exogenous DNA from Clostridium perfringens (69% A + T) or from Micrococcus luteus (30% A + T) induced by 0.6 M NaCl or by 2% formaldehyde were studied by thermal denaturation. The observed redistribution occurred on histone Hl when the exogeno...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00666a002
更新日期：1976-10-19 00:00:00
abstract：:Fructose-1,6-bisphosphate muscle aldolase is an essential glycolytic enzyme that catalyzes reversible carbon-carbon bond formation by cleaving fructose 1,6-bisphosphate to yield dihydroxyacetone phosphate (DHAP) and d-glyceraldehyde phosphate. To elucidate the mechanistic role of conserved amino acid Asp-33, Asn-33 an...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi8021558
更新日期：2009-06-02 00:00:00
abstract：:Human protein Z is a vitamin K-dependent plasma glycoprotein, deficiency of which leads to a mild bleeding tendency. Protein Z appears to assist hemostasis by binding thrombin and promoting its association with phospholipid vesicles. In this study, to characterize the gene for protein Z, its organization and structure...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi972002a
更新日期：1998-05-12 00:00:00
abstract：:The individual amide proton exchange rates in Tendamistat at pH 3.0 and 50 degrees C were measured by using two-dimensional 1H nuclear magnetic resonance. Overall, it was found that the distribution of exchange rates along the sequence is dominated by the interstrand hydrogen bonds of the beta-sheet structures. The sl...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00394a030
更新日期：1987-10-06 00:00:00
abstract：:The effects of nonylphenol and 3,5-dibutyl-4-hydroxytoluene (BHT) on the activity of the (Ca2(+)-Mg2+)-ATPase of skeletal muscle sarcoplasmic reticulum have been studied. At high concentrations, both inhibit the ATPase activity of the ATPase either in native lipid or in bilayers of dioleoylphosphatidylcholine but, at ...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00464a028
更新日期：1990-03-27 00:00:00
abstract：:Aromatic amino acids often flank the transmembrane alpha helices of integral membrane proteins. By favoring locations within the membrane-water interface of the lipid bilayer, aromatic residues Trp, Tyr, and sometimes Phe may serve as anchors to help stabilize a transmembrane orientation. In this work, we compare the ...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi500439x
更新日期：2014-06-10 00:00:00
abstract：:Deletion of Glu146, Thr147, and Trp148 from thrombin dramatically alters its interactions with substrates, ligands, and inhibitors, and the changes appear to result from nonlocal modification of thrombin's structure [Le Bonniec, B. F., Guinto, E. R., & Esmon, C. T. (1992) J. Biol. Chem. 267, 19341-19348]. In an attemp...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00179a023
更新日期：1994-04-05 00:00:00
abstract：:Hepatitis C virus (HCV) protease NS3 and its protein activator NS4A participate in the processing of the viral polyprotein into its constituent nonstructural proteins. The NS3/4A complex is thus an attractive target for antiviral therapy against HCV. We expressed the full-length NS3 and NS4A in insect cells as a solub...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi972010r
更新日期：1998-03-10 00:00:00
abstract：:Recent work has resulted in the development of potent inhibitors of oligosaccharyl transferase (OT), the enzyme that catalyzes the cotranslational glycosylation of asparagine [Hendrickson, T. L., Spencer, J. R., Kato, M., and Imperiali, B. (1996) J. Am. Chem. Soc. 118, 7636-7637; Kellenberger, C., Hendrickson, T. L., ...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi982740e
更新日期：1999-04-27 00:00:00
abstract：:Disruption of the zinc-thiolate center at the active site of yeast alcohol dehydrogenase results in inactivation and zinc release. Measurements of activity, zinc release, and thiol/thiolate oxidation were used to assess the effects of biologically relevant oxidants on alcohol dehydrogenase. Alcohol dehydrogenase was i...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00011a008
更新日期：1995-03-21 00:00:00
abstract：:Cytochrome P450 BM-3 is a bacterial enzyme with sequence similarity to mammalian P450s that catalyzes the hydroxylation of fatty acids with high efficiency. Enzyme-substrate binding and dynamics has been an important topic of study for cytochromes P450 because most of the crystal structures of substrate-bound structur...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi4000645
更新日期：2013-10-01 00:00:00
abstract：:Bacterial NO synthase (NOS)-like proteins such as that from Bacillus subtilis (bsNOS) share a high degree of structural homology with the oxygenase domain of mammalian NOSs (mNOSs), but biochemical studies have yet failed to establish that they are specifically capable of producing NO. To better understand the actual ...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi051710q
更新日期：2006-02-07 00:00:00
abstract：:The electron spin resonance probes 5-doxylstearate and 4-(dodecyldimethylammonio)-1-oxy-2,2,6,6-tetramethylpiperidine bromide were used to characterize the fluidity of the acyl chain and head-group regions, respectively, of defined salts of lipopolysaccharide (LPS) from Escherichia coli K12. The removal of the weakly ...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00277a042
更新日期：1983-04-12 00:00:00
abstract：:Genetic knockout of the BtR4 gene encoding the Heliothis virescens cadherin-like protein (HevCaLP) is linked to resistance against Cry1Ac toxin from Bacillus thuringiensis. However, the functional Cry1Ac receptor role of this protein has not been established. We previously proposed HevCaLP as a shared binding site for...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi0606703
更新日期：2006-08-15 00:00:00
abstract：:A statistical mechanical partition function for phospholipid bilayers is constructed to obtain a theoretical description of the chain melting phase transition in lipid bilayer membranes and of the phase diagrams for two-component bilayers. In addition to providing an accurate representation of the transition temperatu...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00639a004
更新日期：1977-10-04 00:00:00
abstract：:In prokaryotes, a large share of the proteins are secreted from the cell through a process that requires their translocation across the cytoplasmic membrane. This process is mediated by the universally conserved Sec system with homologues in the endoplasmic reticulum and thylakoid membranes of eukaryotes. The Sec syst...
journal_title：Biochemistry
pub_type： 杂志文章,评审
doi：10.1021/bi400913x
更新日期：2013-10-01 00:00:00
abstract：:A soluble and fully functional 10.5 kDa fragment of the 18.2 kDa membrane-bound cytochrome c(552) from Paracoccus denitrificans has been heterologously expressed and (13)C/(15)N-labeled to study the structural features of this protein in both redox states. Well-resolved solution structures of both the reduced and oxid...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi010615o
更新日期：2001-10-16 00:00:00
abstract：:The interaction of spin-labeled lipids with the myelin proteolipid apoprotein in complexes with dimyristoylphosphatidylcholine of varying lipid/protein ratios has been studied with electron spin resonance spectroscopy. A first shell of approximately 10 lipids per 25 000-dalton protein is found to be motionally restric...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00300a011
更新日期：1984-02-28 00:00:00
abstract：:The structure of HIV protease (HIV Pr) bound to JE-2147 (also named AG1776 or KNI-764) is determined here to 1.09 A resolution. This highest-resolution structure for HIV Pr allows refinement of anisotropic displacement parameters (ADPs) for all atoms. Clustering based on the directional information in ADPs defines two...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi011781z
更新日期：2002-04-09 00:00:00
abstract：:A recirculating Langendorff heart preparation is used to characterize the endogenous antithrombin associated reversibly with murine vascular endothelium. Rat hearts are perfused clear of blood and then recirculated with a physiological salt solution. Addition of heparin educes antithrombin activity continuously into t...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi00169a024
更新日期：1994-01-25 00:00:00
abstract：:The fetal Alz-50 reactive clone 1 (FAC1) protein exhibits altered expression and subcellular localization during neuronal development and neurodegenerative diseases such as Alzheimer's disease. Using the yeast two-hybrid screen, the human orthologue of Keap1 (hKeap1) was identified as a FAC1 interacting protein. Keap1...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi0494166
更新日期：2004-09-28 00:00:00
abstract：:The reaction of nitric oxide (NO) with fast cytochrome bo from Escherichia coli has been studied by electronic absorption, MCD, and EPR spectroscopy. Titration of the enzyme with NO showed the formation of two distinct species, consistent with NO binding stoichiometries of 1:1 and 2:1 with observed dissociation consta...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi971481a
更新日期：1997-12-23 00:00:00
abstract：:Unoccupied estrogen receptor (ER) can be extracted from tissues by homogenization with a hypotonic buffer, whereas hormone-occupied ER becomes tightly bound to the nuclear pellet and must be extracted with high-salt-containing buffers. The molecular basis for estrogen-induced tight nuclear binding of ER remains an imp...
journal_title：Biochemistry
pub_type： 杂志文章
doi：10.1021/bi982190k
更新日期：1999-06-01 00:00:00
