scholarly journals Isolation and Expression of the xynB Gene and Its Product, XynB, a Consistent Component of the Clostridium cellulovorans Cellulosome

2004 ◽  
Vol 186 (24) ◽  
pp. 8347-8355 ◽  
Author(s):  
Sung Ok Han ◽  
Hideaki Yukawa ◽  
Masayuki Inui ◽  
Roy H. Doi
Keyword(s):  
Amino Acid ◽  
Nucleotide Sequence ◽  
Amino Acid Sequence ◽  
Catalytic Domain ◽  
Transcriptional Start Site ◽  
Glycosyl Hydrolase ◽  
Pcr Analysis ◽  
Carbohydrate Binding ◽  
Clostridium Cellulovorans ◽  
Race Pcr

ABSTRACT The nucleotide sequence of the Clostridium cellulovorans xynB gene, which encodes the XynB xylanase, consists of 1,821 bp and encodes a protein of 607 amino acids with a molecular weight of 65,976. XynB contains a typical N-terminal signal peptide of 29 amino acid residues, followed by a 147-amino-acid sequence that is homologous to the family 4-9 (subfamily 9 in family 4) carbohydrate-binding domain. Downstream of this domain is a family 10 catalytic domain of glycosyl hydrolase. The C terminus separated from the catalytic domain by a short linker sequence contains a dockerin domain responsible for cellulosome assembly. The XynB sequence from mass spectrometry and N-terminal amino acid sequence analyses agreed with that deduced from the nucleotide sequence. XynB was highly active toward xylan, but not active toward carboxymethyl cellulose. The enzyme was optimally active at 40°C and pH 5.0. Northern hybridizations revealed that xynB is transcribed as a monocistronic 1.9-kb mRNA. RNA ligase-mediated rapid amplification of 5′ cDNA ends by PCR (RLM-5′RACE PCR) analysis of C. cellulovorans RNA identified a single transcriptional start site of xynB located 47 bp upstream from the first nucleotide of the translation initiation codon. Alignment of the xynB promoter region provided evidence for highly conserved sequences that exhibited strong similarity to the σA consensus promoter sequences of gram-positive bacteria. Expression of xynB mRNA increased from early to middle exponential phase and decreased during the early stationary phase when the cells were grown on cellobiose. No alternative promoter was observed by RLM-5′RACE PCR and reverse transcriptase PCR analyses during expression. The analysis of the products from xylan hydrolysis by thin-layer chromatography indicated its endoxylanase activity. The results suggest that XynB is a consistent and major cellulosomal enzyme during growth on cellulose or xylan.

scholarly journals Molecular Cloning and Transcriptional and Expression Analysis of engO, Encoding a New Noncellulosomal Family 9 Enzyme, from Clostridium cellulovorans

2005 ◽  
Vol 187 (14) ◽  
pp. 4884-4889 ◽  
Author(s):  
Sung Ok Han ◽  
Hideaki Yukawa ◽  
Masayuki Inui ◽  
Roy H. Doi
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Nucleotide Sequence ◽  
Catalytic Domain ◽  
Transcriptional Start Site ◽  
Glycosyl Hydrolase ◽  
Mass Spectrometry Analysis ◽  
Pcr Analysis ◽  
Carbohydrate Binding ◽  
Clostridium Cellulovorans

ABSTRACT Clostridium cellulovorans produces a major noncellulosomal family 9 endoglucanase EngO. A genomic DNA fragment (40 kb) containing engO and neighboring genes was cloned. The nucleotide sequence contained reading frames for endoglucanase EngO, a putative response regulator, and a putative sensor histidine kinase protein. The engO gene consists of 2,172 bp and encodes a protein of 724 amino acids with a molecular weight of 79,474. Northern hybridizations revealed that the engO gene is transcribed as a monocistronic 2.6-kb mRNA. 5′ RNA ligase-mediated rapid amplification of cDNA ends (RLM-RACE) PCR analysis indicated that the single transcriptional start site of engO was located 264 bp upstream from the first nucleotide of the translation initiation codon. Alignment of the engO promoter region provided evidence for highly conserved sequences that exhibited strong similarity to the σA consensus promoter sequences of gram-positive bacteria. EngO contains a typical N-terminal signal peptide of 28 amino acid residues, followed by a 149-amino-acid sequence which is homologous to the family 4-9 carbohydrate-binding domain. Downstream of this domain was an immunoglobulin-like domain of 89 amino acids. The C terminus contains a family 9 catalytic domain of glycosyl hydrolase. Mass spectrometry analysis of EngO was in agreement with that deduced from the nucleotide sequence. Expression of engO mRNA increased from early to middle exponential phase and decreased during the early stationary phase. EngO was highly active toward carboxymethyl cellulose but showed no activity towards xylan. It was optimally active at 40 to 50°C and pH 5 to 6. The analysis of the products from the cellulose hydrolysis through thin-layer chromatography indicated its endoglucanase activity.

Characteristics of a cluster of xylanase genes inFibrobacter succinogenesS85

2003 ◽  
Vol 49 (3) ◽  
pp. 171-180 ◽  
Author(s):  
Hyun S Jun ◽  
Jong K Ha ◽  
Laercio M Malburg, Jr. ◽  
Ann M Verrinder Gibbins ◽  
Cecil W Forsberg
Keyword(s):  
Catalytic Domain ◽  
Specific Activity ◽  
Glycosyl Hydrolase ◽  
Amino Acid Sequences ◽  
Pcr Analysis ◽  
Carbohydrate Binding ◽  
Fibrobacter Succinogenes ◽  
Rt Pcr ◽  
Ph Optimum ◽  
Oat Spelt

Xylanase genes xyn10D, xyn10E, and xyn10B, located sequentially on the Fibrobacter succinogenes S85 chromosome, were separately cloned and their properties characterized. Analysis of the sequences documented that xylanases Xyn10D, Xyn10E, and Xyn10B each consist of an N-terminal catalytic domain (glycosyl hydrolase family 10) and a C-terminal carbohydrate-binding module (CBM, family 6) connected by proline-rich linker sequences. The amino acid sequences exhibited similarities of between 53 and 60%. The xyn10D, xyn10E, and truncated xyn10BΔCBM were expressed in Escherichia coli and purified to homogeneity. The purified Xyn10D, Xyn10E, and Xyn10BΔCBM exhibited the same temperature optimum (40°C) and pH optimum (6.5) and the highest specific activity against arabinoxylan, oat spelt xylan, and birchwood xylan, respectively. Xyn10D exhibited an affinity for cellulose and xylan with 47 and 33% binding, respectively, while the truncated Xyn10DΔCBM did not bind to the substrates. The main hydrolysis products of the three xylanases acting on oat spelt xylan and arabinoxylan were xylose and xylobiose. RT-PCR analysis showed that the three genes were co-transcribed as a single transcript. Western immunoblot analysis revealed that the three xylanases were expressed at a very low level by F. succinogenes grown on either glucose or cellulose as the source of carbohydrate.Key words: Fibrobacter succinogenes S85, xylan, xylanase, clustered genes, RT-PCR.

scholarly journals Nucleotide sequence of the melB gene and characteristics of deduced amino acid sequence of the melibiose carrier in Escherichia coli.

1984 ◽  
Vol 259 (7) ◽  
pp. 4320-4326 ◽  
Author(s):  
H Yazyu ◽  
S Shiota-Niiya ◽  
T Shimamoto ◽  
H Kanazawa ◽  
M Futai ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Nucleotide Sequence ◽  
Amino Acid Sequence

scholarly journals Terminal deoxynucleotidyltransferase. Alignment of α- and β-subunits of the core enzyme along the primary translation product

1985 ◽  
Vol 227 (3) ◽  
pp. 1003-1007 ◽  
Author(s):  
C M Beach ◽  
S K Chan ◽  
T C Vanaman ◽  
M S Coleman
Keyword(s):  
Amino Acid ◽  
Nucleotide Sequence ◽  
Amino Acid Sequence ◽  
Beta Subunits ◽  
Isolation And Purification ◽  
C Terminus ◽  
Human Lymphoblast ◽  
Catalytically Active ◽  
Single Polypeptide ◽  
Dna Nucleotide Sequence

Terminal deoxynucleotidyltransferase exists in multiple Mr forms, all apparently generated from a single polypeptide of 62kDa. On isolation and purification, the smallest catalytically active protein of this enzyme consists of two subunits, alpha (12kDa) and beta (30kDa). Recently a complementary-DNA nucleotide sequence has been reported for a portion of the enzyme from human lymphoblast. We have pinpointed the locations of the alpha- and beta-subunits within the elucidated nucleotide sequence. From these data, the portions of the nucleotide sequence coding for the catalytically important area of the transferase can be estimated. Here the amino acid sequence of a number of tryptic peptides from calf alpha- and beta-subunits is presented. Because of the striking homology between the amino acid sequence of the calf enzyme and that predicted for human lymphoblast enzyme, it is possible for us to conclude that the alpha-subunit was generated from the C-terminus of the precursor protein and the beta-subunit was non-overlapping and proximal.

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