scholarly journals A Large Gene Cluster for the Clostridium cellulovorans Cellulosome

2000 ◽  
Vol 182 (20) ◽  
pp. 5906-5910 ◽  
Author(s):  
Yutaka Tamaru ◽  
Shuichi Karita ◽  
Atef Ibrahim ◽  
Helen Chan ◽  
Roy H. Doi

ABSTRACT A large gene cluster for the Clostridium cellulovoranscellulosome has been cloned and sequenced upstream and downstream of the cbpA and exgS genes (C.-C. Liu and R. H. Doi, Gene 211:39–47, 1998). Gene walking revealed that theengL gene cluster (Y. Tamaru and R. H. Doi, J. Bacteriol. 182:244–247, 2000) was located downstream of thecbpA-exgS genes. Further DNA sequencing revealed that this cluster contains the genes for the scaffolding protein CbpA, the exoglucanase ExgS, several endoglucanases of family 9, the mannanase ManA, and the hydrophobic protein HbpA containing a surface layer homology domain and a hydrophobic (or cohesin) domain. The sequence of the clustered genes iscbpA-exgS-engH-engK-hbpA-engL-manA-engM-engN and is about 22 kb in length. The engN gene did not have a complete catalytic domain, indicating that engN is a truncated gene. This large gene cluster is flanked at the 5′ end by a putative noncellulosomal operon consisting of nifV-orf1-sigX-regAand at the 3′ end by noncellulosomal genes with homology to transposase (trp) and malate permease (mle). Since gene clusters for the cellulosome are also found in C. cellulolyticum and C. josui, they seem to be typical of mesophilic clostridia, indicating that the large gene clusters may arise from a common ancestor with some evolutionary modifications.

2002 ◽  
Vol 184 (4) ◽  
pp. 884-888 ◽  
Author(s):  
Akihiko Kosugi ◽  
Koichiro Murashima ◽  
Yutaka Tamaru ◽  
Roy H. Doi

ABSTRACT engE, coding for endoglucanase E, one of the three major subunits of the Clostridium cellulovorans cellulosome, has been cloned and sequenced (Y. Tamaru and R. H. Doi, J. Bacteriol. 181:3270-3276, 1999). The N-terminal-half region of EngE possesses three repeated surface layer homology (SLH) domains, which are homologous to those of some bacterial S-layer proteins. Also, the C-terminal-half region consists of a catalytic domain of glycosyl hydrolase family 5 and a duplicated sequence (dockerin) for binding EngE to scaffolding protein CbpA. Our hypothesis is that the SLH domains serve in the role of anchoring to the cell surface. This model was investigated by using recombinant EngEs (rEngE) with and without SLH domains that were synthesized in Escherichia coli and cell wall preparations from C. cellulovorans. When rEngE and SLH polypeptides of EngE were incubated with cell wall fragments prepared by sodium dodecyl sulfate treatment, these proteins bound strongly to the cell wall. However, rEngEs without SLH domains lost their ability to bind to cell walls. When rEngE was incubated with mini-CbpA, consisting of two cohesin domains, and cell wall fragments, the mini-CbpA was able to bind to the cell wall with rEngE. However, the binding of mini-CbpA was dramatically inhibited by addition of a chelating reagent, such as EDTA, which prevents cohesin-dockerin interactions. These results suggest not only that the SLH domains of EngE can bind to the cell surface but also that EngE plays an anchoring role for cellulosomes through the interaction of its dockerin domain with a CbpA cohesin.


1999 ◽  
Vol 181 (10) ◽  
pp. 3270-3276 ◽  
Author(s):  
Yutaka Tamaru ◽  
Roy H. Doi

ABSTRACT The gene engE, coding for endoglucanase E, one of the three major subunits of the Clostridium cellulovoranscellulosome, has been isolated and sequenced. engE is comprised of an open reading frame (ORF) of 3,090 bp and encodes a protein of 1,030 amino acids with a molecular weight of 111,796. The amino acid sequence derived from engE revealed a structure consisting of catalytic and noncatalytic domains. The N-terminal-half region of EngE consisted of a signal peptide of 31 amino acid residues and three repeated surface layer homology (SLH) domains, which were highly conserved and homologous to an S-layer protein from the gram-negative bacterium Caulobacter crescentus. The C-terminal-half region, which is necessary for the enzymatic function of EngE and for binding of EngE to the scaffolding protein CbpA, consisted of a catalytic domain homologous to that of family 5 of the glycosyl hydrolases, a domain of unknown function, and a duplicated sequence (DS or dockerin) at its C terminus. engE is located downstream of an ORF, ORF1, that is homologous to theBacillus subtilis phosphomethylpyrimidine kinase (pmk) gene. The unique presence of three SLH domains and a DS suggests that EngE is capable of binding both to CbpA to form a CbpA-EngE cellulosome complex and to the surface layer of C. cellulovorans.


2007 ◽  
Vol 189 (20) ◽  
pp. 7190-7194 ◽  
Author(s):  
Satoshi Matsuoka ◽  
Hideaki Yukawa ◽  
Masayuki Inui ◽  
Roy H. Doi

ABSTRACT Clostridium cellulovorans, an anaerobic bacterium, produces a small nonenzymatic protein called HbpA, which has a surface layer homology domain and a type I cohesin domain similar to those found in the cellulosomal scaffolding protein CbpA. In this study, we demonstrated that HbpA could bind to cell wall fragments from C. cellulovorans and insoluble polysaccharides and form a complex with cellulosomal cellulases endoglucanase B (EngB) and endoglucanase L (EngL). Synergistic degradative action of the cellulosomal cellulase and HbpA complexes was demonstrated on acid-swollen cellulose, Avicel, and corn fiber. We propose that HbpA functions to bind dockerin-containing cellulosomal enzymes to the cell surface and complements the activity of cellulosomes.


2013 ◽  
Vol 79 (21) ◽  
pp. 6803-6812 ◽  
Author(s):  
Ave Tooming-Klunderud ◽  
Hanne Sogge ◽  
Trine Ballestad Rounge ◽  
Alexander J. Nederbragt ◽  
Karin Lagesen ◽  
...  

ABSTRACTHorizontal gene transfer is common in cyanobacteria, and transfer of large gene clusters may lead to acquisition of new functions and conceivably niche adaption. In the present study, we demonstrate that horizontal gene transfer between closely relatedPlanktothrixstrains can explain the production of the same oligopeptide isoforms by strains of different colors. Comparison of the genomes of eightPlanktothrixstrains revealed that strains producing the same oligopeptide isoforms are closely related, regardless of color. We have investigated genes involved in the synthesis of the photosynthetic pigments phycocyanin and phycoerythrin, which are responsible for green and red appearance, respectively. Sequence comparisons suggest the transfer of a functional phycoerythrin gene cluster generating a red phenotype in a strain that is otherwise more closely related to green strains. Our data show that the insertion of a DNA fragment containing the 19.7-kb phycoerythrin gene cluster has been facilitated by homologous recombination, also replacing a region of the phycocyanin operon. These findings demonstrate that large DNA fragments spanning entire functional gene clusters can be effectively transferred between closely related cyanobacterial strains and result in a changed phenotype. Further, the results shed new light on the discussion of the role of horizontal gene transfer in the sporadic distribution of large gene clusters in cyanobacteria, as well as the appearance of red and green strains.


2000 ◽  
Vol 66 (5) ◽  
pp. 2274-2277 ◽  
Author(s):  
Zhihao Hu ◽  
David A. Hopwood ◽  
Chaitan Khosla

ABSTRACT The biosynthesis of complex natural products in bacteria is invariably encoded within large gene clusters. Although this facilitates the cloning of such gene clusters, their heterologous expression in genetically amenable hosts remains a challenging problem, principally due to the difficulties associated with manipulating large DNA fragments. Here we describe a new method for the directed transfer of a gene cluster from one Streptomyces species to another. The method takes advantage of tra gene-mediated conjugal transfer of chromosomal DNA between actinomycetes. As proof of principle, we demonstrate transfer of the entire ∼22-kb actinorhodin gene cluster, and also the high-frequency cotransfer of two loci that are 150 to 200 kb apart, from Streptomyces coelicolor to an engineered derivative of Streptomyces lividans.


2004 ◽  
Vol 186 (19) ◽  
pp. 6536-6543 ◽  
Author(s):  
Gabrielle Samuel ◽  
John-Paul Hogbin ◽  
Lei Wang ◽  
Peter R. Reeves

ABSTRACT Escherichia coli O157, Salmonella enterica O30, and Citrobacter freundii F90 have identical O-antigen structures, as do E. coli O55 and S. enterica O50. The O-antigen gene cluster sequences for E. coli O157 and E. coli O55 have been published, and the genes necessary for O-antigen biosynthesis have been identified, although transferase genes for glycosidic linkages are only generic and have not been allocated to specific linkages. We determined sequences for S. enterica O30 and C. freundii F90 O-antigen gene clusters and compared them to the sequence of the previously described E. coli O157 cluster. We also determined the sequence of the S. enterica O50 O-antigen gene cluster and compared it to the sequence of the previously described E. coli O55 cluster. For both the S. enterica O30-C. freundii F90-E. coli O157 group and the S. enterica O50-E. coli O55 group of O antigens, the gene clusters have identical or nearly identical organizations. The two sets of gene clusters had comparable overall levels of similarity in their genes, which were lower than the levels determined for housekeeping genes for these species, which were 55 to 65% for the genes encoding glycosyltransferases and O-antigen processing proteins and 75 to 93% for the nucleotide-sugar pathway genes. Nonetheless, the similarity of the levels of divergence in the five gene clusters required us to consider the possibility that the parent gene cluster for each structure was in the common ancestor of the species and that divergence is faster than expected for the common ancestor hypothesis. We propose that the identical O-antigen gene clusters originated from a common ancestor, and we discuss some possible explanations for the increased rate of divergence that is seen in these genes.


2020 ◽  
Author(s):  
Anjan Venkatesh ◽  
Anthony L. Murray ◽  
Aisling Y. Coughlan ◽  
Kenneth H. Wolfe

AbstractIn many yeast species the three genes at the center of the galactose catabolism pathway, GAL1, GAL10 and GAL7, are neighbors in the genome and form a metabolic gene cluster. We report here that some yeast strains in the genus Torulaspora have much larger GAL clusters that include genes for melibiase (MEL1), galactose permease (GAL2), glucose transporter (HGT1), phosphoglucomutase (PGM1), and the transcription factor GAL4, in addition to GAL1, GAL10, and GAL7. Together, these 8 genes encode almost all the steps in the pathway for catabolism of extracellular melibiose (a disaccharide of galactose and glucose). We show that a progenitor 5-gene cluster containing GAL 7-1-10-4-2 was likely present in the common ancestor of Torulaspora and Zygotorulaspora. It added PGM1 and MEL1 in the ancestor of most Torulaspora species. It underwent further expansion in the T. pretoriensis clade, involving the fusion of three progenitor clusters in tandem and the gain of HGT1. These giant GAL clusters are highly polymorphic in structure, and subject to horizontal transfers, pseudogenization and gene losses. We identify recent horizontal transfers of complete GAL clusters from T. franciscae into one strain of T. delbrueckii, and from a relative of T. maleeae into one strain of T. globosa. The variability and dynamic evolution of GAL clusters in Torulaspora indicates that there is strong natural selection on the GAL pathway in this genus.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Woo Cheol Lee ◽  
Sungjae Choi ◽  
Ahjin Jang ◽  
Kkabi Son ◽  
Yangmee Kim

AbstractSome Gram-negative bacteria harbor lipids with aryl polyene (APE) moieties. Biosynthesis gene clusters (BGCs) for APE biosynthesis exhibit striking similarities with fatty acid synthase (FAS) genes. Despite their broad distribution among pathogenic and symbiotic bacteria, the detailed roles of the metabolic products of APE gene clusters are unclear. Here, we determined the crystal structures of the β-ketoacyl-acyl carrier protein (ACP) reductase ApeQ produced by an APE gene cluster from clinically isolated virulent Acinetobacter baumannii in two states (bound and unbound to NADPH). An in vitro visible absorption spectrum assay of the APE polyene moiety revealed that the β-ketoacyl-ACP reductase FabG from the A. baumannii FAS gene cluster cannot be substituted for ApeQ in APE biosynthesis. Comparison with the FabG structure exhibited distinct surface electrostatic potential profiles for ApeQ, suggesting a positively charged arginine patch as the cognate ACP-binding site. Binding modeling for the aryl group predicted that Leu185 (Phe183 in FabG) in ApeQ is responsible for 4-benzoyl moiety recognition. Isothermal titration and arginine patch mutagenesis experiments corroborated these results. These structure–function insights of a unique reductase in the APE BGC in comparison with FAS provide new directions for elucidating host–pathogen interaction mechanisms and novel antibiotics discovery.


Toxins ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 19 ◽  
Author(s):  
Maria B. Nowakowska ◽  
François P. Douillard ◽  
Miia Lindström

The botulinum neurotoxin (BoNT) has been extensively researched over the years in regard to its structure, mode of action, and applications. Nevertheless, the biological roles of four proteins encoded from a number of BoNT gene clusters, i.e., OrfX1-3 and P47, are unknown. Here, we investigated the diversity of orfX-p47 gene clusters using in silico analytical tools. We show that the orfX-p47 cluster was not only present in the genomes of BoNT-producing bacteria but also in a substantially wider range of bacterial species across the bacterial phylogenetic tree. Remarkably, the orfX-p47 cluster was consistently located in proximity to genes coding for various toxins, suggesting that OrfX1-3 and P47 may have a conserved function related to toxinogenesis and/or pathogenesis, regardless of the toxin produced by the bacterium. Our work also led to the identification of a putative novel BoNT-like toxin gene cluster in a Bacillus isolate. This gene cluster shares striking similarities to the BoNT cluster, encoding a bont/ntnh-like gene and orfX-p47, but also differs from it markedly, displaying additional genes putatively encoding the components of a polymorphic ABC toxin complex. These findings provide novel insights into the biological roles of OrfX1, OrfX2, OrfX3, and P47 in toxinogenesis and pathogenesis of BoNT-producing and non-producing bacteria.


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