Cited by 101Lipid metabolism and biosynthesisSteroid Chemistry and BiochemistryMicrobial bioremediation and biosurfactants

Identification and characterization of Rhodopseudomonas palustris TIE‐1 hopanoid biosynthesis mutants

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WELANDER, P. V., DOUGHTY, D. M., WU, C.‐H., MEHAY, S., SUMMONS, R. E., NEWMAN, D. K.·2012·Geobiology

Abstract

Hopanes preserved in both modern and ancient sediments are recognized as the molecular fossils of bacteriohopanepolyols, pentacyclic hopanoid lipids. Based on the phylogenetic distribution of hopanoid production by extant bacteria, hopanes have been used as indicators of specific bacterial groups and/or their metabolisms. However, our ability to interpret them ultimately depends on understanding the physiological roles of hopanoids in modern bacteria. Toward this end, we set out to identify genes required for hopanoid biosynthesis in the anoxygenic phototroph Rhodopseudomonas palustris TIE‐1 to enable selective control of hopanoid production. We attempted to delete 17 genes within a putative hopanoid biosynthetic gene cluster to determine their role, if any, in hopanoid biosynthesis. Two genes, hpnH and hpnG, are required to produce both bacteriohopanetetrol and aminobacteriohopanetriol, whereas a third gene, hpnO, is required only for aminobacteriohopanetriol production. None of the genes in this cluster are required to exclusively synthesize bacteriohopanetetrol, indicating that at least one other hopanoid biosynthesis gene is located elsewhere on the chromosome. Physiological studies with the different deletion mutants demonstrated that unmethylated and C 30 hopanoids are sufficient to maintain cytoplasmic but not outer membrane integrity. These results imply that hopanoid modifications, including methylation of the A‐ring and the addition of a polar head group, may have biologic functions beyond playing a role in membrane permeability.

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Crossref · 10.1111/j.1472-4669.2011.00314.x

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  • 2-methylbacteriohopanepolyols, once thought to be produced only by cyanobacteria, are produced by other bacteria as well.

    “For example, although 2-methyl hopanes are known to be the breakdown product of 2-methylbacteriohopanepolyols, which were once thought to be produced only by cyanobacteria, it has recently been shown that 2-methylbacteriohopanepolyols are produced by other bacteria as well (Rashby et al., 2007; Welander et al., 2012).”

    From The Astrobiology Primer v2.0 (2016) · cites this paper as Welander et al., 2012

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Authors
WELANDER, P. V., DOUGHTY, D. M., WU, C. ‐., MEHAY, S., SUMMONS, R. E., & NEWMAN, D. K.
Affiliations
  • Massachusetts Institute of Technology (US)
  • California Institute of Technology (US)
Corresponding author
NEWMAN, D. K.
Venue
Geobiology
Publisher
Wiley
Published
2012-01-04
Volume
10
Issue
2
Pages
163-177
ISSN
  • 1472-4669 (ISSN-L)
  • 1472-4677
OpenAlex
W2132626170
Cited by
101
References
73
Citations by year
2026: 5 · 2025: 5 · 2024: 3 · 2023: 3 · 2022: 8 · 2021: 6 · 2020: 4 · 2019: 11 · 2018: 6 · 2017: 6 · 2016: 7 · 2015: 15 · 2014: 13 · 2013: 6 · 2012: 3
FWCI
5.07
Type
journal article
Language
en
Open access
Locations
  • Geobiology (publishedVersion)
  • PubMed (publishedVersion)
  • PubMed Central (acceptedVersion)
  • CaltechAUTHORS (California Institute of Technology) (submittedVersion)
  • PMC
Funders
Howard Hughes Medical Institute
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Biochemistry › Lipid metabolism and biosynthesis
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Steroid Chemistry and Biochemistry
  • Physical Sciences › Environmental Science › Pollution › Microbial bioremediation and biosurfactants
Keywords
hopanoid biosynthesis, bacteriohopanepolyols, hopanes, molecular fossils, deletion mutants, bacteriohopanetetrol, outer membrane integrity, plasma membrane integrity, anoxygenic phototrophs
MeSH terms
Bacterial Proteins, Cell Membrane Permeability, Multigene Family, Lipids, Mutation, Rhodopseudomonas, Triterpenes, Gene Deletion

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