Novel Rhamnosyltransferase Involved in Biosynthesis of Serovar 4-Specific Glycopeptidolipid from Mycobacterium avium Complex

ABSTRACT Glycopeptidolipids (GPLs) are one of the major glycolipid components present on the surface of Mycobacterium avium complex (MAC) that belong to opportunistic pathogens distributed in the natural environment. The serovars of MAC, up to around 30 types, are defined by the variable oligosaccharide portions of the GPLs. Epidemiological studies show that serovar 4 is the most prevalent type, and the prognosis of pulmonary disease caused by serovar 4 is significantly worse than that caused by other serovars. However, little is known about the biosynthesis of serovar 4-specific GPL, particularly the formation of the oligosaccharide portion that determines the properties of serovar 4. To investigate the biosynthesis of serovar 4-specific GPL, we focused on one segment that included functionally unknown genes in the GPL biosynthetic gene cluster of a serovar 4 strain. In this segment, a putative hemolytic protein gene, hlpA, and its downstream gene were found to be responsible for the formation of the 4-O-methyl-rhamnose residue, which is unique to serovar 4-specific GPL. Moreover, functional characterization of the hlpA gene revealed that it encodes a rhamnosyltransferase that transfers a rhamnose residue via 1→4 linkage to a fucose residue of serovar 2-specific GPL, which is a key pathway leading to the synthesis of oligosaccharide of serovar 4-specific GPL. These findings may provide clues to understanding the biological role of serovar 4-specific GPL in MAC pathogenicity and may also provide new insights into glycosyltransferase, which generates structural and functional diversity of GPLs.

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Characterization of the AMP-binding protein gene family in Arabidopsis thaliana: will the real acyl-CoA synthetases please stand up?

Biochemical Society Transactions ◽

10.1042/bst0280955 ◽

2000 ◽

Vol 28 (6) ◽

pp. 955-957 ◽

Cited By ~ 8

Author(s):

J. Shockey ◽

J. Schnurr ◽

J. Browse

Keyword(s):

Protein Gene ◽

De Novo ◽

Functional Characterization ◽

De Novo Synthesis ◽

Triacylglycerol Composition ◽

Sequence Comparisons ◽

Triacylglycerol Metabolism ◽

Binding Protein Gene

One of the most prominent and important topics in modern agricultural biotechnology is the manipulation of oilseed triacylglycerol composition. Towards this goal, we have sought to identify and characterize acyl-CoA synthetases (ACSs), which play an important role in both de novo synthesis and modification of existing lipids. We have identified and cloned 20 different genes that bear strong sequence homology to known ACSs from other organisms. Through sequence comparisons and functional characterization, we have identified several members of this group that encode ACSs, while the other genes fall into the broader category of genes for AMP-binding proteins (AMPBPs). Distinguishing ACSs from AMPBPs will simplify our efforts to understand the role of ACS in triacylglycerol metabolism.

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Functional characterization of host toxic EcdB transcription factor protein of echinocandin B biosynthetic gene cluster

Biotechnology and Applied Biochemistry ◽

10.1002/bab.1763 ◽

2019 ◽

Vol 66 (4) ◽

pp. 626-633

Author(s):

Arvind Kumar ◽

Vinay Kumar ◽

Antresh Kumar

Keyword(s):

Transcription Factor ◽

Gene Cluster ◽

Functional Characterization ◽

Biosynthetic Gene Cluster ◽

Biosynthetic Gene ◽

Echinocandin B

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Characterization of the Fucosylation Pathway in the Biosynthesis of Glycopeptidolipids from Mycobacterium avium Complex

Journal of Bacteriology ◽

10.1128/jb.00344-07 ◽

2007 ◽

Vol 189 (15) ◽

pp. 5515-5522 ◽

Cited By ~ 8

Author(s):

Yuji Miyamoto ◽

Tetsu Mukai ◽

Yumi Maeda ◽

Noboru Nakata ◽

Masanori Kai ◽

...

Keyword(s):

Mycobacterium Avium ◽

Mycobacterium Smegmatis ◽

Chromosomal Region ◽

Nontuberculous Mycobacteria ◽

Functional Characterization ◽

Amino Acid Sequences ◽

Surface Molecules ◽

Cell Envelopes ◽

Fucose Residue

ABSTRACT The cell envelopes of several species of nontuberculous mycobacteria, including the Mycobacterium avium complex, contain glycopeptidolipids (GPLs) as major glycolipid components. GPLs are highly antigenic surface molecules, and their variant oligosaccharides define each serotype of the M. avium complex. In the oligosaccharide portion of GPLs, the fucose residue is one of the major sugar moieties, but its biosynthesis remains unclear. To elucidate it, we focused on the 5.0-kb chromosomal region of the M. avium complex that includes five genes, two of which showed high levels of similarity to the genes involved in fucose synthesis. For the characterization of this region by deletion and expression analyses, we constructed a recombinant Mycobacterium smegmatis strain that possesses the rtfA gene of the M. avium complex to produce serovar 1 GPL. The results revealed that the 5.0-kb chromosomal region is responsible for the addition of the fucose residue to serovar 1 GPL and that the three genes mdhtA, merA, and gtfD are indispensable for the fucosylation. Functional characterization revealed that the gtfD gene encodes a glycosyltransferase that transfers a fucose residue via 1→3 linkage to a rhamnose residue of serovar 1 GPL. The other two genes, mdhtA and merA, contributed to the formation of the fucose residue and were predicted to encode the enzymes responsible for the synthesis of fucose from mannose based on their deduced amino acid sequences. These results indicate that the fucosylation pathway in GPL biosynthesis is controlled by a combination of the mdhtA, merA, and gtfD genes. Our findings may contribute to the clarification of the complex glycosylation pathways involved in forming the oligosaccharide portion of GPLs from the M. avium complex, which are structurally distinct.

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Functional characterization of KanP, a methyltransferase from the kanamycin biosynthetic gene cluster of Streptomyces kanamyceticus

Microbiological Research ◽

10.1016/j.micres.2009.11.002 ◽

2010 ◽

Vol 165 (7) ◽

pp. 557-564

Author(s):

Keshav Kumar Nepal ◽

Jin Cheol Yoo ◽

Jae Kyung Sohng

Keyword(s):

Gene Cluster ◽

Functional Characterization ◽

Biosynthetic Gene Cluster ◽

Biosynthetic Gene ◽

Streptomyces Kanamyceticus

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Organization of the biosynthetic gene cluster in Streptomyces sp. DSM 4137 for the novel neuroprotectant polyketide meridamycin

Microbiology ◽

10.1099/mic.0.29176-0 ◽

2006 ◽

Vol 152 (12) ◽

pp. 3507-3515 ◽

Cited By ~ 21

Author(s):

Yuhui Sun ◽

Hui Hong ◽

Markiyan Samborskyy ◽

Tatiana Mironenko ◽

Peter F. Leadlay ◽

...

Keyword(s):

Neurodegenerative Disorders ◽

Gene Deletion ◽

Polyketide Synthase ◽

Biosynthetic Gene Cluster ◽

Specific Gene ◽

The Novel ◽

Biosynthetic Gene ◽

Modular Polyketide Synthase

Meridamycin is a non-immunosuppressant, FKBP-binding macrocyclic polyketide, which has major potential as a neuroprotectant in a range of neurodegenerative disorders including dementia, Parkinson's disease and ischaemic stroke. A biosynthetic cluster predicted to encode biosynthesis of meridamycin was cloned from the prolific secondary-metabolite-producing strain Streptomyces sp. DSM 4137, not previously known to produce this compound, and specific gene deletion was used to confirm the role of this cluster in the biosynthesis of meridamycin. The meridamycin modular polyketide synthase consists of 14 extension modules distributed between three giant multienzyme proteins. The terminal module is flanked by a highly unusual cytochrome P450-like domain. The characterization of the meridamycin biosynthetic locus in this readily manipulated streptomycete species opens the way to the engineering of new, altered meridamycins of potential therapeutic importance.

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Identification of a lysine 4-hydroxylase from the glidobactin biosynthesis and evaluation of its biocatalytic potential

Organic & Biomolecular Chemistry ◽

10.1039/c8ob02054j ◽

2019 ◽

Vol 17 (7) ◽

pp. 1736-1739 ◽

Cited By ~ 8

Author(s):

Alexander Amatuni ◽

Hans Renata

Keyword(s):

Gene Cluster ◽

Functional Characterization ◽

Biosynthetic Gene Cluster ◽

Biosynthetic Gene

We present the functional characterization of GlbB, a lysine 4-hydroxylase from the glidobactin biosynthetic gene cluster.

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Role of the FeoB Protein and Siderophore in Promoting Virulence of Xanthomonas oryzae pv. oryzae on Rice

Journal of Bacteriology ◽

10.1128/jb.01558-09 ◽

2010 ◽

Vol 192 (12) ◽

pp. 3187-3203 ◽

Cited By ~ 47

Author(s):

Alok Pandey ◽

Ramesh V. Sonti

Keyword(s):

Gene Cluster ◽

Functional Characterization ◽

Biosynthetic Gene Cluster ◽

Xanthomonas Oryzae ◽

In Planta ◽

Growth Deficiency ◽

Constitutive Production ◽

Serious Disease

ABSTRACT Xanthomonas oryzae pv. oryzae causes bacterial blight, a serious disease of rice. Our analysis revealed that the X. oryzae pv. oryzae genome encodes genes responsible for iron uptake through FeoB (homolog of the major bacterial ferrous iron transporter) and a siderophore. A mutation in the X. oryzae pv. oryzae feoB gene causes severe virulence deficiency, growth deficiency in iron-limiting medium, and constitutive production of a siderophore. We identified an iron regulated xss gene cluster, in which xssABCDE ( X anthomonas siderophore synthesis) and xsuA ( X anthomonas siderophore utilization) genes encode proteins involved in biosynthesis and utilization of X. oryzae pv. oryzae siderophore. Mutations in the xssA, xssB, and xssE genes cause siderophore deficiency and growth restriction under iron-limiting conditions but are virulence proficient. An xsuA mutant displayed impairment in utilization of native siderophore, suggesting that XsuA acts as a specific receptor for a ferric-siderophore complex. Histochemical and fluorimetric assays with gusA fusions indicate that, during in planta growth, the feoB gene is expressed and that the xss operon is not expressed. This study represents the first report describing a role for feoB in virulence of any plant-pathogenic bacterium and the first functional characterization of a siderophore-biosynthetic gene cluster in any xanthomonad.

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The role of the TetR-family transcriptional regulator Aur1R in negative regulation of the auricin gene cluster in Streptomyces aureofaciens CCM 3239

Microbiology ◽

10.1099/mic.0.037895-0 ◽

2010 ◽

Vol 156 (8) ◽

pp. 2374-2383 ◽

Cited By ~ 29

Author(s):

Renata Novakova ◽

Peter Kutas ◽

Lubomira Feckova ◽

Jan Kormanec

Keyword(s):

Gene Cluster ◽

Biosynthetic Gene Cluster ◽

Transcriptional Repressors ◽

Biosynthetic Gene ◽

Response Regulators ◽

Streptomyces Aureofaciens ◽

Two Component Signal Transduction

Two regulatory genes, aur1P and aur1R, have been previously identified upstream of the aur1 polyketide gene cluster involved in biosynthesis of the angucycline-like antibiotic auricin in Streptomyces aureofaciens CCM 3239. The aur1P gene encodes a protein similar to the response regulators of bacterial two-component signal transduction systems and has been shown to specifically activate expression of the auricin biosynthetic genes. The aur1R gene encodes a protein homologous to transcriptional repressors of the TetR family. Here we describe the characterization of the aur1R gene. Expression of the gene is directed by a single promoter, aur1Rp, which is induced just before stationary phase. Disruption of aur1R in S. aureofaciens CCM 3239 had no effect on growth and differentiation. However, the disrupted strain produced more auricin than its parental wild-type S. aureofaciens CCM 3239 strain. Transcription from the aur1Ap and aur1Pp promoters, directing expression of the first biosynthetic gene in the auricin gene cluster and the pathway-specific transcriptional activator, respectively, was increased in the S. aureofaciens CCM 3239 aur1R mutant strain. However, Aur1R was shown to bind specifically only to the aur1Pp promoter in vitro. This binding was abolished by the addition of auricin and/or its intermediates. The results indicate that the Aur1R regulator specifically represses expression of the aur1P gene, which encodes a pathway-specific activator of the auricin biosynthetic gene cluster in S. aureofaciens CCM 3239, and that this repression is relieved by auricin or its intermediates.

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