Biochemical functions of corrinoid compounds. The sixth Hopkins memorial lecture

Barker, H. A.

doi:10.1042/bj1050001

Cited by 77 publications

(22 citation statements)

References 115 publications

(38 reference statements)

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“…In contrast to MetH, NrdJ is more selective in the cobamides it can use (Fig. 4A), as expected based on studies with other class II RNRs (33, 36, 51, 52). There was little growth with [Cre]Cba, [Phe]Cba, and [5-OHBza]Cba (Fig.…”

Section: Resultssupporting

confidence: 81%

Flexible cobamide metabolism in Clostridioides (Clostridium) difficile 630 Δerm

Shelton

Lyu

Taga

2019

Preprint

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11Clostridioides (Clostridium) difficile is an opportunistic pathogen known for its ability to 12 colonize the human gut under conditions of dysbiosis. Several aspects of its carbon and amino 13 acid metabolism have been investigated, but its cobamide (vitamin B 12 and related cofactors) 14 metabolism remains largely unexplored. C. difficile has seven predicted cobamide-dependent 15 metabolisms encoded in its genome in addition to a nearly complete cobamide biosynthesis 16 pathway and a cobamide uptake system. To address the importance of cobamides to C. difficile, 17we studied C. difficile 630 ∆erm and mutant derivatives under cobamide-dependent conditions in 18 vitro. Our results show that C. difficile can use a surprisingly diverse array of cobamides for 19 methionine and deoxyribonucleotide synthesis, and can use alternative metabolites or enzymes, 20 respectively, to bypass these cobamide-dependent processes. C. difficile 630 ∆erm produces the 21 cobamide pseudocobalamin when provided the early precursor 5-aminolevulinc acid or the late 22 metabolic pathways that are predicted to require cobamide-dependent enzymes. Here, we show 34 that C. difficile cobamide metabolism is versatile, as it can use a surprisingly wide variety of 35 cobamides and has alternative functions that can bypass some of its cobamide requirements. 36 Furthermore, C. difficile does not synthesize cobamides de novo, but produces them when given 37 cobamide precursors. Better understanding of C. difficile cobamide metabolism may lead to new 38 strategies to treat and prevent C. difficile-associated disease. 383This work was supported by grants NIH DP2AI117984 and R01GM114535 to M.E.T. 384 385We thank Aimee Shen for her extensive advice and protocols for working with C. difficile, Craig

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Section: Resultssupporting

confidence: 81%

Flexible cobamide metabolism in Clostridioides (Clostridium) difficile 630 Δerm

Shelton

Lyu

Taga

2019

Preprint

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“…Such an observation is logical since the β-Glc Y molecule is small enough to penetrate the intercellular space of plant tissues, but too large to cross the plasma membrane [26]. Since β-Glc Y is known to interact with AGPs [23,18,25] our results could suggest that β-Glc Y co-localised with cell wall AGPs.…”

Section: Resultsmentioning

confidence: 89%

Identification of novel genes potentially involved in somatic embryogenesis in chicory (Cichorium intybus L.)

et al. 2010

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BackgroundIn our laboratory we use cultured chicory (Cichorium intybus) explants as a model to investigate cell reactivation and somatic embryogenesis and have produced 2 chicory genotypes (K59, C15) sharing a similar genetic background. K59 is a responsive genotype (embryogenic) capable of undergoing complete cell reactivation i.e. cell de- and re-differentiation leading to somatic embryogenesis (SE), whereas C15 is a non-responsive genotype (non-embryogenic) and is unable to undergo SE. Previous studies [1] showed that the use of the β-D-glucosyl Yariv reagent (β-GlcY) that specifically binds arabinogalactan-proteins (AGPs) blocked somatic embryo production in chicory root explants. This observation indicates that β-GlcY is a useful tool for investigating somatic embryogenesis (SE) in chicory. In addition, a putative AGP (DT212818) encoding gene was previously found to be significantly up-regulated in the embryogenic K59 chicory genotype as compared to the non-embryogenic C15 genotype suggesting that this AGP could be involved in chicory re-differentiation [2]. In order to improve our understanding of the molecular and cellular regulation underlying SE in chicory, we undertook a detailed cytological study of cell reactivation events in K59 and C15 genotypes, and used microarray profiling to compare gene expression in these 2 genotypes. In addition we also used β-GlcY to block SE in order to identify genes potentially involved in this process.ResultsMicroscopy confirmed that only the K59, but not the C15 genotype underwent complete cell reactivation leading to SE formation. β-GlcY-treatment of explants blocked in vitro SE induction, but not cell reactivation, and induced cell wall modifications. Microarray analyses revealed that 78 genes were differentially expressed between induced K59 and C15 genotypes. The expression profiles of 19 genes were modified by β-GlcY-treatment. Eight genes were both differentially expressed between K59 and C15 genotypes during SE induction and transcriptionally affected by β-GlcY-treatment: AGP (DT212818), 26 S proteasome AAA ATPase subunit 6 (RPT6), remorin (REM), metallothionein-1 (MT1), two non-specific lipid transfer proteins genes (SDI-9 and DEA1), 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-CoA reductase), and snakin 2 (SN2). These results suggest that the 8 genes, including the previously-identified AGP gene (DT212818), could be involved in cell fate determination events leading to SE commitment in chicory.ConclusionThe use of two different chicory genotypes differing in their responsiveness to SE induction, together with β-GlcY-treatment represented an efficient tool to discriminate cell reactivation from the SE morphogenetic pathway. Such an approach, together with microarray analyses, permitted us to identify several putative key genes related to the SE morphogenetic pathway in chicory.

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“…This reaction appears to be complex involving a phosphate-dependent dehydration and internal oxidoreduction. It bears some resemblance to the vitamin Bl2-dependent dioldehydratases [26] but no studies on the reaction mechanism have yet been made.…”

Section: Discussionmentioning

confidence: 99%