摘要:

SummaryThescrgenes located on plasmid pUR400 and responsible for sAucrose (Scr) metabolism ofEscherichia coliK12 and other enteric bacteria have been cloned on a 9.3 kb DNA fragment. The different genes were mapped by transposon insertion mutagenesis, by restriction endonuclease and deletion mapping, and the corresponding gene products were identified. Besides the known structural genesscrA, coding for an EnzymellScr(45 kD) of the phosphoenolypyruvate‐dependent phosphotransferase system (PTS), andscrB, coding for a sucrose 6‐phosphate hydrolase (invertase) (55 kD), two new structural genes were discovered. GenescrKapparently codes for an intracellular and ATP‐dependent fructokinase (39 kD), whilescryseems to code for a sucrose porin (58 kD) in the outer cell membrane. No genes for an Enzyme IIIScrof the PTS or for (a) glycosyltransferase(s) were detected. The four genes form anscroperon (gene order,scrK scrY scrA scrB, transcription from K to B), regulated by a repressor (genescrR, 37 kD) and inducible by sucrose, fructose and fructose‐containing oligosac

ISSN:0950-382X    

DOI:10.1111/j.1365-2958.1988.tb00001.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

SummaryThe nucleotide sequence of the structural gene,scrA, which codes for sucrose‐specific EnzymellScr(EIIScr) of the phosphoenolpyruvate‐dependent carbohydrate: phosphotransferase system (PTS), was determined. EllScrrequires an Enzymelll, the product of the genecrr, for full activity. The genescrAis preceded immediately by a classical Shine‐Dalgarno sequence (AAGAGGGTA). It contains 1368 nucleotides with an increased GC‐content (58%) corresponding to a polypeptide of 455 amino acid residues (Mr47 500). The protein has the hydropathic profile (average hydropathy +0.82) of an integral membrane protein lacking extended α‐helical structures and a signal peptide. Comparison with the sequence of the β‐glucoside‐specific Enzymell (EllBgl, 625 amino acids, Mr66480; Bramley and Kornberg, 1987a; Schnetzet al., 1987) revealed strong homologies between EllScrand the first 458 residues of EllBgl. The 162 carboxyterminal residues of EllBgl, however, showed a high homology with the sequence of Enzymelll (Nelsonet al., 1984), a homology also described recently by Bramley and Kornberg (1987b). The evolutionary and functional significance of the similarities with four other Enzymes

ISSN:0950-382X    

DOI:10.1111/j.1365-2958.1988.tb00002.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

SummaryThe adenylate cyclase toxin of the prokaryoteBordetella pertussisis stimulated by the eukaryotic regulatory protein, calmodulin. A general strategy, using the adenylate‐cyclase‐calmodulin interaction as a tool, has permitted cloning and expression of the toxin inEscherichia coliin the absence of anyB. pertussis trans‐activating factor. We show that the protein is synthesized in a large precursor form composed of 1706 amino acids. The calmodulin‐stimulated catalytic activity resides in the amino‐terminal 450 amino acids of the adenylate cyclase. The enzyme expressed inE. coliis recognized in Western blots by antibodies directed against purifiedB. pertussisadenylate cyclase, and its activity is inhibited by these a

ISSN:0950-382X    

DOI:10.1111/j.1365-2958.1988.tb00003.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

SummaryEscherichia colibacteria produce at least one 70 kD stress protein, the product of thednaKgene. We have compared the rates of degradation of different types of abnormal proteins in nullIon E. coliwith a partial deletion of thednaKgene with the rates observed in nullIon dnaK+cells. We have found that both canavanyl proteins and puromycyl polypeptides are degraded more slowly in the nulldnaKmutants than in thednaK+strain. However, a temperature‐sensitive mutant Lacl protein is degraded more rapidly in the nulldnaKstrain. The stability of this temperature‐sensitive Lad protein was also examined in detail under various other conditi

ISSN:0950-382X    

DOI:10.1111/j.1365-2958.1988.tb00004.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

SummaryRecombinant plasmids which carried portions of theEscherichia coli frdoperon were constructed and their expression examined byin vivocomplementation ofE. ColiMI 1443. This strain lacked a chromosomalfrdoperon and was unable to grow anaerobically on glycerol and fumarate. Introduction of all four fumarate reductase subunits intoE. coliMI1443 was essential for the restoration of growth. The FRD A, FRD B dimer (but neither subunit alone) was active in the benzyl viologen oxidase assay. Both FRD C and FRD D were required for membrane association of fumarate reductase and for the oxidation of reduced quinone analogues. Introduction intoE. coliMI1443 of thefrdABCandfrdDgenes on two separate plasmid vectors failed to restore anaerobic growth on glycerol and fumarate. Thus separation of the DNA coding for the FRD C and FRD D proteins affected the ability of fumarate reductase to assemble into a functional complex.

ISSN:0950-382X    

DOI:10.1111/j.1365-2958.1988.tb00005.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

SummaryThe genes encoding the three terminal enzymes in the threonine biosynthetic pathway, homoserine dehydrogenasa (hom), homoserine kinase (thrB) and threonine synthase (thrC) have been isolated fromCorynebacterium glutamicum.TheC. glutamicum homandthrBgenes were subcloned on a 3.6 kbSall‐generated chromosomal fragment. TheC. glutamicum thrCgene was shown not to be linked to thehom‐thrBlocus. L‐methionine represses the cloned homoserine dehydrogenase and homoserine kinase similar to that of the chromosomally encodedhomandthrBgene products. Northern hybridization analysis demonstrates that this repression is mediated at the level of transcription and thathom‐thrBrepresents an operon inC. glu

ISSN:0950-382X    

DOI:10.1111/j.1365-2958.1988.tb00006.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

SummaryThe complete nucleotide sequence of theCorynebacterium glutamicum hom‐thrBoperon has been determined and the structural genes and promoter region mapped. A polypeptide of Mr46136 is encoded byhomand a polypeptide of Mr, 32618 is encoded bythrB.Both predicted protein sequences show amino acid sequence homology to their counterparts inEscherichia coliandBacillus subtilis.The promoter region has been mapped by S1‐nuclease and deletion analysis. Located between −88, RNA start site and −219 (smallest deletion clone with complete activity) are sequence elements similar to those found inE. coliandB. subtillspromoters. Although there are no obvious attenuator‐like structures in the 5′‐untranslated region, there is a dyad‐symmetry element, which may act

ISSN:0950-382X    

DOI:10.1111/j.1365-2958.1988.tb00007.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

SummaryThe F71and F71P‐fimbriae ofEscherichia coliare encoded by thefso(F seven one) andfst(F seven two) gene clusters, respectively (Van Dieet al., 1984; 1985).With the immunocytochemical gold‐labelling technique it was demonstrated that both the FsoE and FstE proteins are non‐adhesive minor fimbrial sub‐units located at the tip of the fimbrial structure. The FsoF and FstFG proteins play an important role in the initiation of polymerization of the minor and major subunits into the fimbrial st

ISSN:0950-382X    

DOI:10.1111/j.1365-2958.1988.tb00008.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

SummaryThe three‐dimensional structures of the crystalline surface layers of two species ofEubacteriahave been determined by electron microscopy and computerized image processing. The S‐layer ofEubacteriumsp. ES4C has tetragonal symmetry, with a unit cell spacing of 10.6 nm and a thickness of 9.5 nm, while that ofEubacteriumsp. AHN 990 has hexagonal symmetry a = b = 15.7 nm and a thickness of 13 nm. The resolutions in the reconstructions were 2.5 nm and 1.8 nm, respectively. The reconstruction of the S‐layer of strain ES4C reveals a distinct domain structure: a major tetramer, arms connecting adjacent unit cells, and a minor tetramer. The S‐layer of strain AHN 990, on the other hand, has a rather complex arrangement, centred around the six‐

ISSN:0950-382X    

DOI:10.1111/j.1365-2958.1988.tb00009.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

SummarySubgenomic mRNA from a virulent isolate of porcine transmissible gastroenteritis virus (TGEV) was used to produce cDNA which was sequenced. Two non‐overlapping open reading frames (ORFs) were identified. The largest, encoding a polypeptide of 382 amino acids (relative molecular mass (Mr) 43 483), was shown to be the viral nucleoprotein gene. The second ORF, found 3’to the larger ORF, encodes a polypeptide of 78 amino acids (Mr9068) which has yet to be assigned to a viral product. The nucleoprotein gene was expressed in yeast cells under the control of two types of yeast promoters: the constitutive PGK promoter, and the inducibleGAL1promoter. Yeast cells containing recombinant plasmids, with the nucleoprotein gene in the correct orientation, produced a polypeptide of M, 47000, identical to the viral product, that reacted with a specific monoclonal antib

ISSN:0950-382X    

DOI:10.1111/j.1365-2958.1988.tb00010.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY