Molecular Characterization of Membrane-Associated Soluble Serine Palmitoyltransferases from
            <i>Sphingobacterium multivorum</i>
            and
            <i>Bdellovibrio stolpii</i>

Ikushiro, Hiroko; Islam, Mohammad Mainul; Tojo, Hiromasa; Hayashi, Hideyuki

doi:10.1128/jb.00194-07

Cited by 32 publications

(44 citation statements)

References 77 publications

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“…(267,268) These have supported the general mechanism shown in Figure 5. As for many PLP-dependent enzymes,(269) the amino acid substrate is covalently bound to PLP as a Schiff base 24 (which is often referred to as the “external aldimine” versus the “internal aldimine” that is produced by the enzyme-Lys-PLP Schiff base).…”

Section: Sphingolipid Metabolic Pathwayssupporting

confidence: 77%

Sphingolipid and Glycosphingolipid Metabolic Pathways in the Era of Sphingolipidomics

2011

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Section: Sphingolipid Metabolic Pathwayssupporting

confidence: 77%

Sphingolipid and Glycosphingolipid Metabolic Pathways in the Era of Sphingolipidomics

2011

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“…gov]. In addition, SPT orthologs have been reported in several other sphingolipid-producing bacteria (19,20) and are well conserved in Bacteroides and related species (Table S1). In the following steps, 3-ketosphinganine is converted to sphinganine by 3-ketosphinganine reductase, and sphinganine is further transformed to dihydroceramide by ceramide synthase.…”

Section: Resultsmentioning

confidence: 99%

Membrane sphingolipids as essential molecular signals for Bacteroides survival in the intestine

Bielawski

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

135

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As predominant intestinal symbiotic bacteria, Bacteroides are essential in maintaining the health of the normal mammalian host; in return, the host provides a niche with plentiful nutrients for the symbionts. However, the intestinal environment is replete with chemical, physical, and biological challenges that require mechanisms for prompt and adept sensing of and responses to stress if the bacteria are to survive. Herein we propose that to persist in the intestine Bacteroides take advantage of their unusual bacterial sphingolipids to mediate signaling pathways previously known to be available only to higher organisms. Sphingolipids convey diverse signal transduction and stress response pathways and have profound physiological impacts demonstrated in a variety of eukaryotic cell types. We propose a mechanism by which the formation of specific sphingolipid membrane microdomains initiates signaling cascades that facilitate survival strategies within the bacteria. Our preliminary data suggest that sphingolipid signaling plays an important role in Bacteroides physiology, enabling these bacteria to persist in the intestine and to perform other functions related to symbiosis. stress response | bacterial sphingolipids | lipid rafts T he Bacteroides species make up a predominant genus of bacteria residing within the mammalian intestine. Organisms belonging to this genus have been the subject of extensive research and possess many distinctive features contributing to their ability to flourish in the intestine. For example, Bacteroides have sophisticated ability to degrade polysaccharides (for energy acquisition) (1), pronounced phase variation in surface polysaccharide synthesis (for antigenic versatility) (2, 3), and extensive surface decoration with host glycans (for molecular mimicry) (4). These bacteria display another extremely rare structural feature that has been recognized for decades but remains largely unstudied: membrane sphingolipids. Sphingolipids were generally thought to exist exclusively in eukaryotes until they were discovered in a handful of bacterial and viral lineages (5, 6). What is the function of sphingolipids in bacteria? Are they important in maintaining Bacteroides in their ecological niches? Herein we provide first evidence supporting an important role for sphingolipids in the ability of Bacteroides to survive stress, and we discuss the potential role of sphingolipids in maintaining intestinal symbiotic bacterial populations. Results and DiscussionAre Sphingolipids Important for Bacteroides Growth? Sphingolipids are characterized by an aliphatic amino alcohol sphingoid backbone called long-chain base (LCB). LCB is attached via an amide bond to a fatty acid and via an ester linkage to a polar head group (Fig. 1A). Sphingolipids are always present in eukaryotic cells but are absent in most bacteria, whose membranes comprise only glycerol-based phospholipids (Fig. 1B). However, a few bacterial species possess both phospholipids and sphingolipids. These sphingolipid-containing bacteria are highly r...

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“…The hits against the Sphingobacteriales are particularly intriguing as members of this order are characterized by the presence of cellular lipid components that are comprised of high concentrations of sphingophospholipids [79]. The rate limiting step in sphingolipid biosynthesis in S. multivorum is serine palmitoyltransferase (SPT) [80], as in the E. huxleyi —virus system [81]. Although the EhV SPT is more similar to the host gene (as indicated above), the closest crystal structure in the PDB database to the EhV SPT is Sphingobacterium multivorum [67].…”

Section: Resultsmentioning

confidence: 99%

Coccolithoviruses: A Review of Cross-Kingdom Genomic Thievery and Metabolic Thuggery

Nissimov

Pagarete

et al. 2017

Viruses

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Coccolithoviruses (Phycodnaviridae) infect and lyse the most ubiquitous and successful coccolithophorid in modern oceans, Emiliania huxleyi. So far, the genomes of 13 of these giant lytic viruses (i.e., Emiliania huxleyi viruses—EhVs) have been sequenced, assembled, and annotated. Here, we performed an in-depth comparison of their genomes to try and contextualize the ecological and evolutionary traits of these viruses. The genomes of these EhVs have from 444 to 548 coding sequences (CDSs). Presence/absence analysis of CDSs identified putative genes with particular ecological significance, namely sialidase, phosphate permease, and sphingolipid biosynthesis. The viruses clustered into distinct clades, based on their DNA polymerase gene as well as full genome comparisons. We discuss the use of such clustering and suggest that a gene-by-gene investigation approach may be more useful when the goal is to reveal differences related to functionally important genes. A multi domain “Best BLAST hit” analysis revealed that 84% of the EhV genes have closer similarities to the domain Eukarya. However, 16% of the EhV CDSs were very similar to bacterial genes, contributing to the idea that a significant portion of the gene flow in the planktonic world inter-crosses the domains of life.

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Molecular Characterization of Membrane-Associated Soluble Serine Palmitoyltransferases from Sphingobacterium multivorum and Bdellovibrio stolpii

Cited by 32 publications

References 77 publications

Sphingolipid and Glycosphingolipid Metabolic Pathways in the Era of Sphingolipidomics

Sphingolipid and Glycosphingolipid Metabolic Pathways in the Era of Sphingolipidomics

Membrane sphingolipids as essential molecular signals for Bacteroides survival in the intestine

Coccolithoviruses: A Review of Cross-Kingdom Genomic Thievery and Metabolic Thuggery

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