Analysis of the wee gene cluster responsible for the biosynthesis of the polymeric bioemulsifier from the oil-degrading strain Acinetobacter lwoffii RAG-1 The GenBank/EMBL accession number for the sequence analysis of the eight fragments determined in this work is AJ243431.

Nakar, David; Gutnick, David L.

doi:10.1099/00221287-147-7-1937

Cited by 52 publications

(50 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The putative translation sequence of wzc of RAG-1 exhibited high similarity to several autophosphorylating protein tyrosine kinases involved in polysaccharide biosynthesis in other bacteria (25). In order to examine whether Wzc of RAG-1 is in fact a tyrosine-phosphorylated protein, lysates of the parent, RAG-1 (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Three genes of this cluster, wza, wzb, and wzc, were predicted from sequence homology to be involved in the assembly of emulsan on the cell surface (25). Multimers of the E. coli Wza homologue have been proposed to form an outer membrane pore through which the capsular antigen is translocated (8).…”

mentioning

confidence: 99%

“…Recently, the genes encoding the biosynthetic pathway of apoemulsan were sequenced and localized to a single gene cluster, the wee cluster, consisting of 20 open reading frames (25). Three genes of this cluster, wza, wzb, and wzc, were predicted from sequence homology to be involved in the assembly of emulsan on the cell surface (25).…”

mentioning

confidence: 99%

See 2 more Smart Citations

Involvement of a Protein Tyrosine Kinase in Production of the Polymeric Bioemulsifier Emulsan from the Oil-Degrading StrainAcinetobacter lwoffiiRAG-1

Nakar

Gutnick

2003

J Bacteriol

Self Cite

View full text Add to dashboard Cite

The genes associated with the biosynthesis of the polymeric bioemulsifier emulsan, produced by the oil-degrading Acinetobacter lwoffii RAG-1 are clustered within a 27-kbp region termed the wee cluster. This report demonstrates the involvement of two genes of the wee cluster of RAG-1, wzb and wzc, in emulsan biosynthesis. The two gene products, Wzc and Wzb were overexpressed and purified. Wzc exhibited ATP-dependent autophosphorylating protein tyrosine kinase activity. Wzb was found to be a protein tyrosine phosphatase capable of dephosphorylating the phosphorylated Wzc. Using the synthetic substrate p-nitrophenyl phosphate (PNPP) Wzb exhibited a V max of 12 mol of PNPP min ؊1 mg ؊1 and a K m of 8 mM PNPP at 30°C. The emulsifying activity of mutants lacking either wzb or wzc was 16 and 15% of RAG-1 activity, respectively, suggesting a role for the two enzymes in emulsan production. Phosphorylation of Wzc was found to occur within a cluster of five tyrosine residues at the C terminus. Colonies from a mutant in which these five tyrosine residues were replaced by five phenylalanine residues along with those of a second mutant, which also lacked Wzb, exhibited a highly viscous colony consistency. Emulsan activity of these mutants was 25 and 24% of that of RAG-1, respectively. Neither of these mutants contained cell-associated emulsan. However, they did produce an extracellular high-molecular-mass galactosamine-containing polysaccharide. A model is proposed in which subunit polymerization, translocation and release of emulsan are all associated and coregulated by tyrosine phosphorylation.The hydrocarbon-degrading organism Acinetobacter lwoffii RAG-1 produces an extracellular, polymeric, galactosaminecontaining lipoheteropolysaccharide bioemulsifier (molecular mass, 10 3 kDa), termed emulsan (31, 43). Because of its properties as an emulsion stabilizer, emulsan has been studied extensively and its chemical composition, physical properties, physiology, and fermentation along with its industrial applications have been reviewed (5,16,17). Briefly, emulsan is composed of a linear repeating trisaccharide subunit consisting of N-acyl-D-galactosamine, N-acyl-L-galactosamine uronic acid and 2,4-diamino-6-deoxy-D-glucosamine (2, 16, 43). The amphipathic properties of emulsan are due in part to the presence of about 15% fatty acids covalently bound to the water-soluble biopolymer in both ester and amide linkages (2). During growth on minimal medium, the biopolymer accumulates on the cell surface of exponential-phase RAG-1 cells as a minicapsule and is released into the medium as a protein-polysaccharide complex as the cells approach stationary phase (11,29). The protein-free polysaccharide termed apoemulsan is less effective than emulsan in forming emulsions with hydrophobic substrates, although it does stabilize preformed emulsions (35,42). An exocellular esterase of RAG-1, cloned and sequenced in Escherichia coli, was found to enhance the emulsification of very hydrophobic substrates by apoemulsan in a fashion which did not de...

show abstract

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Involvement of a Protein Tyrosine Kinase in Production of the Polymeric Bioemulsifier Emulsan from the Oil-Degrading StrainAcinetobacter lwoffiiRAG-1

Nakar

Gutnick

2003

J Bacteriol

Self Cite

View full text Add to dashboard Cite

show abstract

“…Acinetobacter surface carbohydrates were first identified and studied in A. venetianus strain RAG-1, leading to the identification of a gene locus required for synthesis and export of the surface carbohydrates (9,10). These carbohydrate synthesis loci are variable yet ubiquitous in A. baumannii (11,12).…”

mentioning

confidence: 99%

Diversity Within the O-linked Protein Glycosylation Systems of Acinetobacter Species

Scott

Kinsella

Edwards

et al. 2014

Molecular & Cellular Proteomics

View full text Add to dashboard Cite

The opportunistic human pathogen Acinetobacter baumannii is a concern to health care systems worldwide because of its persistence in clinical settings and the growing frequency of multiple drug resistant infections. To combat this threat, it is necessary to understand factors associated with disease and environmental persistence of A. baumannii. Recently, it was shown that a single biosynthetic pathway was responsible for the generation of capsule polysaccharide and O-linked protein glycosylation. Because of the requirement of these carbohydrates for virulence and the non-template driven nature of glycan biogenesis we investigated the composition, diversity, and properties of the Acinetobacter glycoproteome. Utilizing global and targeted mass spectrometry methods, we examined 15 strains and found extensive glycan diversity in the O-linked glycoproteome of Acinetobacter. Comparison of the 26 glycoproteins identified revealed that different A. baumannii strains target similar protein substrates, both in characteristics of the sites of O-glycosylation and protein identity. Surprisingly, glycan micro-heterogeneity was also observed within nearly all isolates examined demonstrating glycan heterogeneity is a widespread phenomena in Acinetobacter O-linked glycosylation. By comparing the 11 main glycoforms and over 20 alternative glycoforms characterized within the 15 strains, trends within the glycan utilized for O-linked glycosylation could be observed. These trends reveal Acinetobacter O-linked glycosylation favors short (three to five residue) glycans with limited branching containing negatively charged sugars such as GlcNAc3NAcA4OAc or legionaminic/pseudaminic acid derivatives. These observations suggest that although highly diverse, the capsule/O-linked glycan biosynthetic pathways generate glycans with similar characteristics across all A. baumannii. Molecular & Cellular

show abstract

“…The genes responsible for the biosynthesis and control of emulsan heteropolysaccharide emulsan were also targeted [63]. The genes were cloned, sequenced and shown to exist within a single 27 kbp gene cluster termed as wee regulon in the A. venetianus, but little is known about the protein components of the emulsan complex.…”

Section: Correlation Between Biosurfactant Production and Esterase Acmentioning

confidence: 99%

Biosurfactant Production and Potential Correlation with Esterase Activity

Sekhon¹

2012

J Pet Environ Biotechnol

View full text Add to dashboard Cite

Biosurfactants (microbial surfactants) are surface active compounds produced extracellularly or as part of the cell membrane by several bacterial and fungal species. They have the unique property of reducing the surface and interfacial tension of liquids. Biosurfactants have applications in the field of agriculture, petroleum, microbial enhanced oil recovery, biomedical sciences, cosmetics, food processing and pharmaceuticals. The global biosurfactants market has grown gradually. Regardless of their greater biodegradability and reduced toxicity, cost competitiveness still remains the major concern for biosurfactant production. However, recombinant or metabolically engineered hyper producing strains combined with optimized cultivation conditions have made it possible for many companies to reap the benefits of 'green' biosurfactant technology. Simultaneously, biosurfactants and bioemulsifiers showing esterase activities and having potential applications are reported to form stable oil-water emulsions with hydrophobic substrates such as hexadecane and polyaromatic hydrocarbons. Biosurfactant production and release of esterases by the microbial cells is shown to be synchronized and symbiotically beneficial in some species. Several bacterial biosurfactant and esterase genes have been identified, cloned and expressed for their enhanced production. This

show abstract

Analysis of the wee gene cluster responsible for the biosynthesis of the polymeric bioemulsifier from the oil-degrading strain Acinetobacter lwoffii RAG-1 The GenBank/EMBL accession number for the sequence analysis of the eight fragments determined in this work is AJ243431.

Cited by 52 publications

References 51 publications

Involvement of a Protein Tyrosine Kinase in Production of the Polymeric Bioemulsifier Emulsan from the Oil-Degrading StrainAcinetobacter lwoffiiRAG-1

Involvement of a Protein Tyrosine Kinase in Production of the Polymeric Bioemulsifier Emulsan from the Oil-Degrading StrainAcinetobacter lwoffiiRAG-1

Diversity Within the O-linked Protein Glycosylation Systems of Acinetobacter Species

Biosurfactant Production and Potential Correlation with Esterase Activity

Contact Info

Product

Resources

About