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Taxonomic group: bacteria / Firmicutes (Phylum: Firmicutes)

The structure was elucidated in this paper
NCBI PubMed ID: 31801844
Publication DOI: 10.1128/mSphere.00814-19
Journal NLM ID: 101674533
Publisher: Washington, DC: American Society for Microbiology
Correspondence: Mark C. Herzberg <mcherzb

umn.edu>
Institutions: Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, Minnesota, USA, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, State College, Pennsylvania, USA, Department of Oral Biology, Faculty of Odontology, Malmo University, Malmo, Sweden

Lipoteichoic acid (LTA) is an abundant polymer of the Gram-positive bacterial cell envelope and is essential for many species. Whereas the exact function of LTA has not been elucidated, loss of LTA in some species affects hydrophobicity, biofilm formation, and cell division. Using a viable LTA-deficient strain of the human oral commensal Streptococcus gordonii, we demonstrated that LTA plays an important role in surface protein presentation. Cell wall fractions derived from the wild-type and LTA-deficient strains of S. gordonii were analyzed using label-free mass spectroscopy. Comparisons showed that the abundances of many proteins differed, including (i) SspA, SspB, and S. gordonii 0707 (SGO_0707) (biofilm formation); (ii) FtsE (cell division); (iii) Pbp1a and Pbp2a (cell wall biosynthesis and remodeling); and (iv) DegP (envelope stress response). These changes in cell surface protein presentation appear to explain our observations of altered cell envelope homeostasis, biofilm formation, and adhesion to eukaryotic cells, without affecting binding and coaggregation with other bacterial species, and provide insight into the phenotypes revealed by the loss of LTA in other species of Gram-positive bacteria. We also characterized the chemical structure of the LTA expressed by S. gordonii Similarly to Streptococcus suis, S. gordonii produced a complex type I LTA, decorated with multiple d-alanylations and glycosylations. Hence, the S. gordonii LTA appears to orchestrate expression and presentation of cell surface-associated proteins and functions.IMPORTANCE Discovered over a half-century ago, lipoteichoic acid (LTA) is an abundant polymer found on the surface of Gram-positive bacteria. Although LTA is essential for the survival of many Gram-positive species, knowledge of how LTA contributes to bacterial physiology has remained elusive. Recently, LTA-deficient strains have been generated in some Gram-positive species, including the human oral commensal Streptococcus gordonii The significance of our research is that we utilized an LTA-deficient strain of S. gordonii to address why LTA is physiologically important to Gram-positive bacteria. We demonstrate that in S. gordonii, LTA plays an important role in the presentation of many cell surface-associated proteins, contributing to cell envelope homeostasis, cell-to-cell interactions in biofilms, and adhesion to eukaryotic cells. These data may broadly reflect a physiological role of LTA in Gram-positive bacteria.

cell wall, lipoteichoic acid, gram-positive bacteria, Streptococcus gordonii, LTA, surface proteins

Structure type: oligomer
Location inside paper: fig.2A
Trivial name: LTA type I
Compound class: lipoteichoic acid
Contained glycoepitopes: IEDB_130695,IEDB_142488,IEDB_144998,IEDB_144999,IEDB_146664,IEDB_1597446,IEDB_241118,IEDB_983931,SB_192

Methods: 1H NMR, PCR, DNA sequencing, GC-MS, SDS-PAGE, ESI-MS, Western blotting, genetic methods, LC-MS/MS, SEM, biofilm assay, de-D-alanylation
Comments, role: Proposed structure of S. gordonii type I LTA.

NCBI Taxonomy refs (TaxIDs): 1302
Show glycosyltransferases

There are too many chemically distinct structures (2187) corresponding to the specified structure with alternative fragments (<..>), so only one was processed further:

xDAla?(1-2)[xDAla?(1-2)[xDAla?(1-2)[xDAla?(1-2)[xDAla?(1-2)[xDAla?(1-2)[xDAla?(1-2)[aDGlcp(1-3)]x?Gro(1-P-6)aDGlcp(1-3)]x?Gro(1-P-6)aDGlcp(1-3)]x?Gro(1-P-6)aDGlcp(1-3)x?Gro(1-P-3)]x?Gro(1-P-3)]x?Gro(1-P-3)]x?Gro(1-P-3)]x?Gro(1-P

There is only one chemically distinct structure for the variant above:

C[C@@H](N)C(=O)OC(CO[C@H]1O[C@H](COP(=O)(O)OCC(CO[C@H]2O[C@H](COP(=O)(O)OCC(CO[C@H]3O[C@H](CO)[C@@H](O)[C@H](O)[C@H]3O)OC(=O)[C@@H](C)N)[C@@H](O)[C@H](O)[C@H]2O)OC(=O)[C@@H](C)N)[C@@H](O)[C@H](O)[C@H]1O)COP(=O)(O)OC[C@H]1O[C@H](OCC(O)COP(=O)(O)OCC(COP(=O)(O)OCC(COP(=O)(O)OCC(COP(=O)(O)OCC(COP(=O)(O)O)OC(=O)[C@@H](C)N)OC(=O)[C@@H](C)N)OC(=O)[C@@H](C)N)OC(=O)[C@@H](C)N)[C@H](O)[C@@H](O)[C@@H]1O

SVG MW SMILES 3D mol Ionize

Warning = sub-repeat ending at xXP?: unknown unit count was assumed to be 3
Warning = sub-repeat ending at xXP?: unknown unit count was assumed to be 3

Taxonomic group: fungi / Ascomycota (Phylum: Ascomycota)

The structure was elucidated in this paper
NCBI PubMed ID: 34584120
Publication DOI: 10.1038/s41598-021-98474-y
Journal NLM ID: 101563288
Publisher: London: Nature Publishing Group
Correspondence: encarnac

ccg.unam.mx
Institutions: Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México, CAS Biotechnology, Parque Científico y Tecnológico de Morelos, Xochitepec, México

Nitrogen-fixing bacteria have been extensively studied in the context of interactions with their host plants; however, little is known about the phenotypic plasticity of these microorganisms in nonmutualistic interactions with other eukaryotes. A dual-species coculture model was developed by using the plant symbiotic bacterium Rhizobium etli and the well-studied eukaryote Saccharomyces cerevisiae as a tractable system to explore the molecular mechanisms used by R. etli in nonmutual interactions. Here, we show that the fungus promotes the growth of the bacterium and that together, these organisms form a mixed biofilm whose biomass is ~ 3 times greater and is more structured than that of either single-species biofilm. We found that these biofilm traits are dependent on a symbiotic plasmid encoding elements involved in the phenotypic plasticity of the bacterium, mitochondrial function and in the production of a yeast-secreted sophoroside. Interestingly, the promoters of 3 genes that are key in plant bacteria-interaction (nifH, fixA and nodA) were induced when R. etli coexists with yeast. These results show that investigating interactions between species that do not naturally coexist is a new approach to discover gene functions and specialized metabolites in model organisms.

Saccharomyces cerevisiae, yeast, sophoroside

Structure type: oligomer ; 794.26 [M+H]+
C₃₀H₅₀O₂₄
Location inside paper: Fig. 4, Sc2A
Compound class: glycoside
Contained glycoepitopes: IEDB_140628,IEDB_142488,IEDB_146664,IEDB_983931,SB_192

Methods: 13C NMR, 1H NMR, NMR-2D, IR, FAB-MS, DNA techniques, biological assays, extraction, optical rotation measurement, RP-HPLC, cell growth, confocal scanning laser microscopy, gene expression, DNA extraction, evaporation, sonication, centrifugation, biofilm assay
Biological activity: compound affects the growth of Rhizobium etli strains that do not harbor the symbiotic plasmid and plasmid A
Comments, role: NMR temperature was not specified

NCBI Taxonomy refs (TaxIDs): 4932
Show glycosyltransferases

NMR conditions: in CD3OD

¹H NMR data: present in publication

¹³C NMR data: present in publication

There is only one chemically distinct structure:

O=C(CCC(=O)CO[C@@H]1O[C@H](CO)[C@@H](O)[C@H](O)[C@H]1O[C@@H]1O[C@H](CO)[C@@H](O)[C@H](O)[C@H]1O)CO[C@@H]1O[C@H](CO)[C@@H](O)[C@H](O)[C@H]1O[C@@H]1O[C@H](CO)[C@@H](O)[C@H](O)[C@H]1O

SVG MW SMILES 3D mol Ionize