Molecular characterization of the interferon-induced 15-kDa protein. Molecular cloning and nucleotide and amino acid sequence.

We present here the isolation and molecular characterization of acetolactate synthase (ALS) genes from the cyanobacterium Synechococcus PCC7942 which specify a sulfonylurea-sensitive enzyme and from the sulfonylurea-resistant mutant SM3/20, which specify resistance to sulfonylurea herbicides. The ALS gene was cloned and mapped by complementation of an Escherichia coli ilv auxotroph that requires branched-chain amino acids for growth and lacks ALS activity. The cyanobacterial gene is efficiently expressed in this heterologous host. The ALS gene codes for 612 amino acids and shows high sequence homology (46%) at the amino acid level with ALS III of E. coli and with the tobacco ALS. The resistant phenotype is a consequence of proline to serine substitution in residue 115 of the deduced amino acid sequence. Functional expression of the mutant gene in wild-type Synechococcus and in E. coli confirmed that this amino-acid substitution is responsible for the resistance. Yet the deduced amino-acid sequence as compared with othjer ALS proteins supports the notion that the amino-acid context of the substitution is important for the resistance.

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Molecular characterization of the M genomic segment of the Seoul 80-39 virus; nucleotide and amino acid sequence comparisons with other hantaviruses reveal the evolutionary pathway

Virus Research ◽

10.1016/0168-1702(91)90093-b ◽

1991 ◽

Vol 19 (1) ◽

pp. 47-58 ◽

Cited By ~ 23

Author(s):

Dragana Antic ◽

Byung-Uk Lim ◽

C.Yong Kang

Keyword(s):

Amino Acid ◽

Amino Acid Sequence ◽

Molecular Characterization ◽

Genomic Segment ◽

Sequence Comparisons ◽

Evolutionary Pathway

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Molecular Characterization of a Novel Glucosyltransferase from Lactobacillus reuteri Strain 121 Synthesizing a Unique, Highly Branched Glucan with α-(1→4) and α-(1→6) Glucosidic Bonds

Applied and Environmental Microbiology ◽

10.1128/aem.68.9.4283-4291.2002 ◽

2002 ◽

Vol 68 (9) ◽

pp. 4283-4291 ◽

Cited By ~ 80

Author(s):

S. Kralj ◽

G. H. van Geel-Schutten ◽

H. Rahaoui ◽

R. J. Leer ◽

E. J. Faber ◽

...

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Amino Acid Sequence ◽

Molecular Characterization ◽

Lactobacillus Reuteri ◽

Degenerate Primers ◽

Terminal Domain ◽

Branching Points ◽

Culture Supernatants

ABSTRACT Lactobacillus reuteri strain 121 produces a unique, highly branched, soluble glucan in which the majority of the linkages are of the α-(1→4) glucosidic type. The glucan also contains α-(1→6)-linked glucosyl units and 4,6-disubstituted α-glucosyl units at the branching points. Using degenerate primers, based on the amino acid sequences of conserved regions from known glucosyltransferase (gtf) genes from lactic acid bacteria, the L. reuteri strain 121 glucosyltransferase gene (gtfA) was isolated. The gtfA open reading frame (ORF) was 5,343 bp, and it encodes a protein of 1,781 amino acids with a deduced M r of 198,637. The deduced amino acid sequence of GTFA revealed clear similarities with other glucosyltransferases. GTFA has a relatively large variable N-terminal domain (702 amino acids) with five unique repeats and a relatively short C-terminal domain (267 amino acids). The gtfA gene was expressed in Escherichia coli, yielding an active GTFA enzyme. With respect to binding type and size distribution, the recombinant GTFA enzyme and the L. reuteri strain 121 culture supernatants synthesized identical glucan polymers. Furthermore, the deduced amino acid sequence of the gtfA ORF and the N-terminal amino acid sequence of the glucosyltransferase isolated from culture supernatants of L. reuteri strain 121 were the same. GTFA is thus responsible for the synthesis of the unique glucan polymer in L. reuteri strain 121. This is the first report on the molecular characterization of a glucosyltransferase from a Lactobacillus strain.

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