Abstract：
:To elucidate the strategy of low temperature adaptation for a cold-adapted family 8 xylanase, the thermal and chemical stabilities, thermal inactivation, thermodependence of activity and conformational flexibility, as well as the thermodynamic basis of these processes, were compared with those of a thermophilic homolog. Differential scanning calorimetry, fluorescence monitoring of guanidine hydrochloride unfolding and fluorescence quenching were used, among other techniques, to show that the cold-adapted enzyme is characterized by a high activity at low temperatures, a poor stability and a high flexibility. In contrast, the thermophilic enzyme is shown to have a reduced low temperature activity, high stability and a reduced flexibility. These findings agree with the hypothesis that cold-adapted enzymes overcome the quandary imposed by low temperature environments via a global or local increase in the flexibility of their molecular edifice, with this in turn leading to a reduced stability. Analysis of the guanidine hydrochloride unfolding, as well as the thermodynamic parameters of irreversible thermal unfolding and thermal inactivation shows that the driving force for this denaturation and inactivation is a large entropy change while a low enthalpy change is implicated in the low temperature activity. A reduced number of salt-bridges are believed to be responsible for both these effects. Guanidine hydrochloride unfolding studies also indicate that both family 8 enzymes unfold via an intermediate prone to aggregation.
journal_name
J Mol Bioljournal_title
Journal of molecular biologyauthors
Collins T,Meuwis MA,Gerday C,Feller Gdoi
10.1016/s0022-2836(03)00287-0keywords:
subject
Has Abstractpub_date
2003-04-25 00:00:00pages
419-28issue
2eissn
0022-2836issn
1089-8638pii
S0022283603002870journal_volume
328pub_type
杂志文章abstract：:A mutant of bovine pancreatic trypsin inhibitor (BPTI) has been constructed and expressed in Escherichia coli in order to probe the kinetic and structural consequences of truncating the binding loop residues to alanine. In addition to two such mutations (Thr11Ala and Pro13Ala), it has a conservative Lys15Arg substitut...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1006/jmbi.1999.3445
更新日期：2000-02-04 00:00:00
abstract：:Cross-links in tendon collagen are essential for the biomechanical strength of healthy tissue. The nature and position of these cross-links has long been a subject for conjecture. We have approached this problem in a non-destructive manner, by studying neutron diffraction from collagen fibrils that have been specifica...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/S0022-2836(05)80115-9
更新日期：1990-05-05 00:00:00
abstract：:The seeds of jack fruit (Artocarpus integrifolia) contain two tetrameric lectins, jacalin and artocarpin. Jacalin was the first lectin found to exhibit the beta-prism I fold, which is characteristic of the Moraceae plant lectin family. Jacalin contains two polypeptide chains produced by a post-translational proteolysi...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1006/jmbi.2001.5432
更新日期：2002-03-22 00:00:00
abstract：:To determine the conformational requirements for antibody recognition and extent of flexibility within a protein epitope, a chimeric influenza A virus neuraminidase (NA) has been constructed in which five discontinuous polypeptide segments from a subtype N9 NA, which comprise the monoclonal antibody NC41 epitope, have...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1006/jmbi.1994.1025
更新日期：1994-01-14 00:00:00
abstract：:A normal mode and energy minimization of ras p21 is used to determine the flexibility of the protein and the origin of the conformational differences between GTP and GDP-bound forms. To preserve the integrity of the structures, a hydration shell of water molecules was included as part of the system. Certain low-freque...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1006/jmbi.1997.1313
更新日期：1997-11-21 00:00:00
abstract：:Proteasomes, major proteolytic sites in eukaryotic cells, play an important part in major histocompatibility class I (MHC I) ligand generation and thus in the regulation of specific immune responses. Their cleavage specificity is of outstanding interest for this process. In order to generalize previously determined cl...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1006/jmbi.2000.3683
更新日期：2000-05-05 00:00:00
abstract：:The X-ray structure of the GCN4-bZIP protein bound to DNA containing the ATF/CREB recognition sequence has been refined at 2.2 A. The water-mediated interactions between the basic domain and DNA are revealed, and combined with a more accurate description of the direct contacts, further clarify how binding specificity ...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1006/jmbi.1995.0645
更新日期：1995-12-08 00:00:00
abstract：:The mechanism by which the binuclear metallophosphotriesterases (PTEs, E.C. 3.1.8.1) catalyse substrate hydrolysis has been extensively studied. The mu-hydroxo bridge between the metal ions has been proposed to be the initiating nucleophile in the hydrolytic reaction. In contrast, analysis of some biomimetic systems h...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2007.10.061
更新日期：2008-02-01 00:00:00
abstract：:The fine folding and assembling characteristics of amyloid beta (Abeta) peptides are important to pharmaceutical studies of drug molecules and to the pathological analysis of neurodegenerative disorders such as Alzheimer's disease at the molecular level. Here we present observations of the multiple folding characteris...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2009.03.054
更新日期：2009-05-15 00:00:00
abstract：:A homologue of the Escherichia coli GroEL apical domain was obtained from thermophilic eubacterium Thermus thermophilus. The domains share 70 % sequence identity (101 out of 145 residues). The thermal stability of the T. thermophilus apical domain (Tm>100 degrees C as evaluated by circular dichroism) is at least 35 de...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1006/jmbi.2000.4405
更新日期：2001-02-23 00:00:00
abstract：:Functional analysis of hepatitis B virus (HBV) core particles has associated a number of biological roles with the C terminus of the capsid protein. One set of functions require the C terminus to be on the exterior of the capsid, while others place this domain on the interior. According to the crystal structure of the...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2007.10.044
更新日期：2008-01-11 00:00:00
abstract：:Expression of the cellular prion protein is necessary for the transmission and propagation of prion diseases. Increasing the level of prion protein expression decreases the incubation period for these diseases. Therefore, understanding the regulation of prion protein expression could be critical for treating or preven...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2007.02.086
更新日期：2007-05-11 00:00:00
abstract：:Nicotine is the principal addictive component of tobacco. Blocking its passage from the lung to the brain with nicotine-specific antibodies is a promising approach for the treatment of smoking addiction. We have determined the crystal structure of nicotine bound to the Fab fragment of a fully human monoclonal antibody...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2011.10.042
更新日期：2012-01-06 00:00:00
abstract：:The structures of the two very closely related proteins, bovine gamma II- and gamma IVa-crystallin have been studied by means of near-ultra-violet linear dichroism spectroscopy on squeezed polyacrylamide gel systems. The crystallin spectra are discussed in terms of the spectra of the aromatic chromophores present in t...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/s0022-2836(05)80069-5
更新日期：1990-11-05 00:00:00
abstract：:The growth of one group of amber mutants of R17 (class A) in non-permissive hosts results in a burst of bacteriophage-like particles, which are defective in that they are non-infectious. Here studies of particles produced by the growth of wild-type R17 and four class A mutants on AB301, a non-permissive Hfr Escherichi...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/0022-2836(66)90016-7
更新日期：1966-11-28 00:00:00
abstract：:Dihydropyrimidinases (hydantoinases) catalyse the reversible hydrolytic ring-opening of cyclic diamides such as dihydropyrimidines in the catabolism of pyrimidines. In biotechnology, these enzymes find application in the enantiospecific production of amino acids from racemic hydantoins. The crystal structure of a D-en...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/S0022-2836(02)00422-9
更新日期：2002-06-28 00:00:00
abstract：:Integration host factor (IHF) of Escherichia coli is a histone-like protein that is involved both in site-specific recombination and in regulating the expression of a number of phage and bacterial genes. We have shown previously that transcription of the ilvGMEDA operon in E. coli is greatly reduced in IHF mutants. We...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/0022-2836(88)90212-4
更新日期：1988-10-05 00:00:00
abstract：:The asymmetric unit membrane (AUM) forms numerous plaques covering the apical surface of mammalian urinary bladder epithelium. These plaques contain four major integral membrane proteins called uroplakins Ia, Ib, II and III, which form particles arranged in a well-ordered hexagonal lattice with p6 symmetry and a latti...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1006/jmbi.1995.0269
更新日期：1995-05-19 00:00:00
abstract：:Export of protein into the periplasm of Escherichia coli via the general secretory system is achieved by action of a ternary complex comprising the polypeptide ligand, the chaperone SecB and SecA, a peripheral component of the membrane translocon, which is itself an ATPase. The unfolded ligand is captured initially by...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2005.08.022
更新日期：2005-10-21 00:00:00
abstract：:The beta-globin gene cluster of human, gorilla and chimpanzee contain the same number and organization of beta-type globin genes: 5'-epsilon (embryonic)-G gamma and A gamma (fetal)-psi beta (inactive)-delta and beta (adult)-3'. We have isolated the psi beta-globin gene regions from the three species and determined the...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/0022-2836(84)90256-0
更新日期：1984-12-25 00:00:00
abstract：:Anthracycline antibiotics daunomycin and adriamycin are among the most widely used in cancer chemotherapy and DNA is believed to be the primary target of their biological action. The crystal structure of a morpholino derivative of adriamycin bound to the DNA hexamer d(CGTACG) has been determined at 1.5 A resolution. T...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1006/jmbi.1993.1208
更新日期：1993-04-05 00:00:00
abstract：:In both prokaryotic and eukaryotic organisms, repressors and activators are responsible for regulating gene expression. The lac operon is a paradigm for understanding how metabolites function as signaling molecules and modulate transcription. These metabolites or allosteric effector molecules bind to the repressor and...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2009.07.050
更新日期：2009-10-09 00:00:00
abstract：:Two-dimensional crystalline porin sheets were obtained by reconstitution of monodisperse protein trimers and phospholipids (dimyristoylphosphatidylcholine) by detergent dialysis, analogous to the reconstitution method used for functional tests (Schindler & Rosenbusch, 1981). Three different packing arrangements were o...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/s0022-2836(83)80275-7
更新日期：1983-04-25 00:00:00
abstract：:The decrease in conformational stability, delta(delta G), has been measured for 72 aliphatic side-chain mutants from four proteins in which a larger side-chain is replaced by a smaller side-chain so that steric effects are minimal. When these delta(delta G) values are corrected to the same accessibility, namely 100% b...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/0022-2836(92)90121-y
更新日期：1992-07-05 00:00:00
abstract：:Phenylalanine hydroxylase from rat liver has been crystallized from polyethylene glycol 4500 with sodium formate. The crystals are tetragonal rods and belong to space group P4(1)22 or P4(3)22 with unit cell dimensions a = b = 57.6 A and c = 304.1 A. They diffract to at least 2.4 A resolution and have one molecule per ...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/0022-2836(91)90694-2
更新日期：1991-04-05 00:00:00
abstract：:The RhaS and RhaR regulatory proteins are encoded in the Escherichia coli L-rhamnose gene cluster. We used complementation analysis and DNA mobility shift assays to show that RhaR is not the direct activator of the L-rhamnose catabolic operon, rhaBAD. An in-frame deletion of rhaS (rhaS-rhaR+) eliminated expression fro...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1006/jmbi.1993.1565
更新日期：1993-11-05 00:00:00
abstract：:The matrix protein of vesicular stomatitis virus (VSV) plays a pivotal role in viral assembly. We previously demonstrated the ability of M protein to self-associate at low salt concentrations. Now, we show the ability of M protein to polymerize in the presence of ZnCl2 in a nucleation-dependent manner. Analysis of kin...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1006/jmbi.1997.1439
更新日期：1997-12-19 00:00:00
abstract：:Plasmodium knowlesi parasites isolated from a rhesus monkey vaccinated with a 143,000/140,000 Mr merozoite surface protein no longer expressed this protein. To study the molecular basis for the mutations, a lambda gt11 cDNA expression library constructed from the original parasite clone was screened with rabbit antise...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/0022-2836(88)90204-5
更新日期：1988-10-05 00:00:00
abstract：:The rate of synthesis and the concentrations of a variety of messenger RNA sequences have been compared between adult mouse liver cells and cells in other adult tissues, and between cells in fetal and neonatal liver. The sequences were distinguished as "liver-specific" or "common" in a previous report, where liver was...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/0022-2836(84)90304-8
更新日期：1984-10-15 00:00:00
abstract：:The streptococcal promiscuous plasmid pMV158 can be mobilized between a number of bacterial species by means of three elements: (i) the plasmid-encoded nicking-closing protein MobM, involved in the initiation and termination of the conjugative transfer; (ii) the DNA sequence where the MobM-mediated nick takes place (t...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2003.11.017
更新日期：2004-01-16 00:00:00
