Biochemistry
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Item Metadata only Effect of sterol structure on the physical-properties and function of plasma-membranes from yeast(Federation of American Societies for Experimental Biology, 1983) BOTTEMA, C.; PARKS, L.Abstract not availableItem Metadata only Control of gene expression in the P2-related template coliphages(Elsevier, 1986) Kalionis, B.; Dodd, I.B.; Egan, J.B.The PstI fragment (65.5% to 77.4%) of coliphage 186, known genetically to encode the major control genes, has been sequenced, and an analysis performed to assess coding capacity, transcription-translation signals, and to identify any other significant features. Our analysis indicates that the region encodes: (1) seven genes, including the int and cI genes, which overlap, the late control gene B, and two genes, named CP75 and CP76, encoding potential DNA-binding proteins; (2) a promoter pB and terminator tB for the rightward transcription of the B gene, and we predict the existence of this transcript in a lysogen; (3) a promoter pL and terminator tL for leftward transcription that encodes the int and cI genes, and represents the presumed lysogenic transcript; (4) a promoter pR for rightward transcription to give the presumed (early) lytic transcript that is overlapping and convergent with the lysogenic transcript; and finally (5), a potential operator site for repressor binding in the region of the pR promoter. Preliminary evidence is presented to support this analysis.Item Metadata only The yeast tribrid system(Nature Publishing Company, 1995) Osborne, M. A.; Dalton, Stephen; Kochar, J.Item Metadata only Mutations in the B-domain of insulin-like growth factor (IGF-I) influence the oxidative folding to yield products with modified biological properties(The Biochemical Society, 1995) Milner, S.; Francis, G.; Wallace, J.; Magee, B.; Ballard, F.The oxidative folding of human insulin-like growth factor (IGF)-I yields two major disulphide folding isomers. In the present study, B-domain analogues of IGF-I were used to investigate the effect of mutations on the folding reaction and to investigate the functional implications of misfolding. The analogues used were substitutions of the native Glu3 by Gly or Arg, or the native Glu9 by Lys. IGF-I and these analogues were also prepared attached to a hydrophobic 13-amino-acid N-terminal extension, Met-Phe-Pro-Ala-Met-Pro-Leu-Ser-Ser-Leu-Phe-Val-Asn, referred to as ‘Long-IGF-I’ analogues. Each IGF was fully reduced and refolded to yield native and misfolded isomers, which were subsequently purified for biological characterization. Analysis of the folding reaction at equilibrium revealed a distribution of folding isomers characteristic for each peptide. The yield of the native disulphide folding isomer was increased for the Glu3 substitutions, but not for the Glu9 substitution. The main alternative folding isomer was present in the IGF-I analogues in reduced proportions. Except for [Gly3]IGF-I the N-terminal extension increased the yield of the native isomer which was maximal for the analogue Long-[Arg3]IGF-I. A folding intermediate for the latter analogue was isolated and partially characterized. The biological assays showed that all the main alternative isomers bound poorly to IGF-binding proteins (IGFBPs) secreted by L6 myoblasts. Moreover, these isomers bound to the type 1 IGF receptor with 0.5-25% the affinity of the native isomer. In a rat L6 myoblast protein-synthesis assay, the observed biological activity of the native and main alternative isomers was explained by their modified IGFBP- and receptor-binding properties. We propose that the N-terminal extension imparts a steric constraint at a crucial point in folding, thus allowing native disulphide bonds to form efficiently.Item Metadata only Cdc54 belongs to the Cdc46 1Mcm3 family of proteins(Elsevier, 1995) Whitbread, L.; Dalton, StephenItem Metadata only Differential changes in milk concentrations of epidermal growth factor and insulin-like growth factor-I during lactation in the tammar wallaby, Macropus eugenii(Academic Press, 1995) Ballard, Francis John; Grobovac, S.; Nicholas, K. R.; Owens, Phillip Clyde; Read, Leanna C.Item Metadata only Cell cycle regulated transcription of the CLB2 gene is dependent on MCMI and a ternay complex factor(American Society for Microbiology, 1995) Maher, M.; Cong, F.; Kindelberger, D.; Nasmyth, K.; Dalton, StephenItem Metadata only Analysis of insulin-like growth factor binding proteins (IGFBPs) in the Tammar wallaby(Academic Press, 1995) Carr, J.; Owens, J.; Baudinette, R.; Wallace, J.Item Metadata only The gene encoding the biotin-apoprotein ligase of Saccharomyces cerevisiae(Elsevier, 1995) Cronan, J.; Wallace, J.Item Metadata only An unusual arrangement of 13 zinc fingers in the vertebrate gene Z13(Biochemical Society, 1995) Schulz, T. C.; Hopwood, Blair; Rathjen, Peter David; Wells, J. R. E.The zinc finger is a protein domain that imparts specific nucleic acid-binding activity on a wide range of functionally important proteins. In this paper we report the molecular cloning and characterization of a novel murine zinc-finger gene, mZ13. Analysis of mZ13 cDNAs revealed that the gene expresses a 794-amino-acid protein encoded by a 2.7 kb transcript. The protein has an unusual arrangement of 13 zinc fingers into a 'hand' of 12 tandem fingers and a single isolated finger near the C-terminus. This structural organization is conserved with the probable chicken homologue, cZ13. mZ13 also contained an additional domain at the N-terminus which has previously been implicated in the regulation of zinc-finger transcription factor DNA-binding, via protein-protein interactions. mZ13 expression was detected in a wide range of murine embryonic and adult tissues. The structural organization of mZ13 and its expression profile suggest that it may function as a housekeeping DNA-binding protein that regulates the expression of specific genes.Item Metadata only Sequence and evolutionary conservation of the murine Gbx-Z homeobox gene(Elsevier, 1995) Chapman, G.; Rathjen, Peter DavidItem Metadata only Two isomeric a and b aspartyl dodecapeptides and their cyclic amino succinyl analogues from the Australian Green Tree Frog Litoria gilleni(CSIRO, 1995) Waugh, R.; Steinborner, S.; Bowie, J.; Wallace, J.; Tyler, M.; Hu, P.; Gross, M.Three related peptides, caeridins 1.1-1.3, have been isolated from the green tree frog Litoria gilleni. Caeridins 1.1 and 1.2 are dodecapeptides differing only in having α and β Asp at residue 4 [viz. Gly Leu Leu Asp Gly Leu Leu Gly Thr Leu Gly Leu (NH2)]. Caeridin 1.3 is the corresponding cyclic amino succinyl derivative derived formally by cyclization of Asp(4) and Gly (5). Hydrolysis of caeridin 1.3 yields caeridin 1.1 and 1.2 in the ratio 3:1. This constitutes a rare case of the isolation of three such related peptides from a natural system.Item Metadata only Extraction from cheese whey by cation-exchange chromatography of factors that stimulate the growth of mammalian cells(Elsevier, 1995) Francis, Geoffrey L.; Regester, Geoffrey Owen; Webb, H. A.; Ballard, Francis JohnItem Metadata only Signalling through Ras: Many targets for anti-cancer therapies?(Eurocommunica Publications, 1995) Booker, G.Item Metadata only DNA sequence of tail fiber genes of coliphage 186 and evidence for a common ancestor shared by dsDNA phage fiber genes(Academic Press, 1995) Qing, X.; Egan, John BarryItem Metadata only Tail sheath and tail tube genes of the temperate coliphage 186(Academic Press Inc., 1995) Qing, X.; Egan, John BarryItem Metadata only Trophic effects of myeloid leukaemia inhibitory factor (LIF) on mouse embryos(Blackwell Scientific Publications, 1995) Lavranos, Tina C.; Rathjen, Peter David; Seamark, Robert F.Item Metadata only Cell cycle-regulated nuclear import and export of Cdc47, a protein essential for initiation of DNA replication in budding yeast(1995) Dalton, Stephen; Whitbread, L.Item Metadata only Molecular defects of erythroid 5-aminolevulinate synthase in X-linked sideroblastic anemia(Plenum Publishing Corporation, 1995) Bottomley, S.; May, B.; Cox, T.; Cotter, P.; Bishop, D.The erythroid-specific isozyme of 5-aminolevulinate synthase (ALAS2), the first and ratelimiting enzyme of heme biosynthesis, is expressed concomitantly with the differentiation and maturation of the erythroid cell in order to accommodate generation of the large amounts of heme required for hemoglobin production. During the past few years the ALAS2 gene and its transcript have been characterized and the amino acid sequence of the enzyme deduced. The human genetic disorder X-linked sideroblastic anemia, previously postulated to be caused by defects of ALAS, has now been analyzed at the molecular and tissue-specific level. A heterogeneous group of point mutations in the catalytic domain of the ALAS2 enzyme has been found to cause the disorder. Impaired activity of recombinant mutant ALAS2 enzymes has also been demonstrated. Characterization of molecular defects in individuals with X-linked sideroblastic anemia has provided improved diagnosis for at-risk family members.Item Metadata only Polymorphism of the yeast pyruvate carboxylase 2 gene and protein: Effects on biotinylation(The Biochemical Society, London, 1995) Val, D.; Chapman-Smith, A.; Walker, M.; Cronan, J.; Wallace, J.In Saccharomyces cerevisiae there are two isoenzymes of pyruvate carboxylase (Pyc) encoded by separate genes designated PYC1 and PYC2. We report the isolation and sequencing of a PYC2 gene, and the localization of both genes on the physical map of S. cerevisiae. Comparison with the previously reported sequence [Stucka, Dequin, Salmon and Gancedo (1991) Mol. Gen. Genet. 229, 307-315] revealed significant differences within the open reading frame. The most notable difference was near the 3' end, where we found a single base deletion reducing the open reading frame by 15 bases. We have confirmed the C-terminus of Pyc2 encoded by the gene isolated here by expressing and purifying an 86-amino-acid biotin-domain peptide. In addition, we investigated the effects of the two changes in the Pyc2 biotin domain (K1155R substitution and Q1178P/five-amino-acid extension) on the extent of biotinylation in vivo by Escherichia coli biotin ligase, and compared the biotinylation of peptides containing these changes with that of two different-length Pyc1 biotin-domain peptides. The K1155R substitution had very little effect on biotinylation, but the five-amino-acid C-terminal extension to Pyc2 and the N-terminal extension to Pycl both improved biotinylation in vivo.