A new mutation in the <i>puf</i>L gene responsible for the terbutryn resistance phenotype in <i>Rubrivivax gelatinosus</i>

Ouchane, Soufian; Picaud, M.; Astier, Chantal

doi:10.1016/0014-5793(95)01055-j

Cited by 22 publications

(3 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…gelatinosus can easily grow under both photosynthetic and respiratory conditions. Its puf operon, containing the photosynthetic genes coding for the RC subunits, has been sequenced and well-characterized for two strains: IL144 (25) and S1 (26,27). Its tetraheme cytochrome subunit shows a high degree of similarity in amino acid sequence with the Blc.…”

mentioning

confidence: 99%

Interaction Site for Soluble Cytochromes on the Tetraheme Cytochrome Subunit Bound to the Bacterial Photosynthetic Reaction Center Mapped by Site-Directed Mutagenesis

et al. 1998

View full text Add to dashboard Cite

The crystallographic structure of the Blastochloris (formerly called Rhodopseudomonas) viridis tetraheme cytochrome subunit bound to the photosynthetic reaction center (RC) suggests that all four hemes are located close enough to the surface of the protein to accept electrons from soluble cytochrome c2. To identify experimentally the site of this reaction we prepared site-directed mutants of Rubrivivax gelatinosus RCs with surface charge substitutions in the bound cytochrome subunit and studied the kinetics of their reduction by soluble cytochromes (mitochondrial horse cytochrome c, Blc. viridis cytochrome c2, and Rvi. gelatinosus cytochrome c8). In comparison with the wild-type, the mutants E79K (glutamate-79 substituted by lysine), E93K (glutamate-93 substituted by lysine), and E85K (glutamate-85 substituted by lysine) located near the solvent-exposed edge of low-potential heme 1, the fourth heme from the special pair of bacteriochlorophyll, exhibited decreased second-order rate constants for the reaction between the tetraheme subunit and the soluble cytochromes. Double charge substitutions in this region: E79K/E85K (glutamate-79 and -85 both replaced by lysine) and E93K/E85K (glutamate-93 and -85 both replaced by lysine) appeared to show an additive inhibitory effect. Mutations in other charged regions did not alter the kinetics of electron transfer between bound and soluble cytochromes. In light of the available structural information on Blc. viridis RC, these results indicate that the cluster of acidic residues immediately surrounding the distal heme 1 of the RC-bound tetraheme subunit forms an electrostatically favorable binding site for soluble cytochromes. Thus, all four hemes in the subunit seem to be directly involved in the electron transfer toward the photo-oxidized special pair of bacteriochlorophyll. On the basis of these findings, a model is proposed for the hypothetical cytochrome c2-RC transient complex for Blc. viridis.

show abstract

mentioning

confidence: 99%

Interaction Site for Soluble Cytochromes on the Tetraheme Cytochrome Subunit Bound to the Bacterial Photosynthetic Reaction Center Mapped by Site-Directed Mutagenesis

et al. 1998

View full text Add to dashboard Cite

show abstract

“…The genes coding for the subunits of LHI and RC and the polypeptides of LHII are organized in operons. The nucleotide sequence of the puf operon has been determined for two strains of R. gelatinosus, strain IL144 (26,27) and strain S1 (28,29); it contains two open reading frames (ORFs) in addition to five photosynthetic genes which have been reported in species belonging to the ␣ subclass. These genes include pufB, -A, -L, -M, and -C coding for the ␤ and ␣ subunits of the B875 light-harvesting protein and for the L, M, and cytochrome subunits of the RC complex, respectively.…”

mentioning

confidence: 99%

Pleiotropic Effects of puf Interposon Mutagenesis on Carotenoid Biosynthesis in Rubrivivax gelatinosus

Ouchane

Picaud

Vernotte

et al. 1997

Journal of Biological Chemistry

View full text Add to dashboard Cite

Rubrivivax gelatinosus mutants affected in the carotenoid biosynthesis pathways were created by interposon mutagenesis within the puf operon. Genetic and biochemical analysis of several constructed mutants suggest that at least crtC is localized downstream of the puf operon and that it is cotranscribed with this operon. Sequence analysis confirmed the genetic data and showed the presence of crtD and crtC genes downstream of the puf operon, a localization different from that known for other purple bacteria. Inactivation of the crtD gene indicated that the two crt genes are cotranscribed and that they are involved not only in the hydroxyspheroidene biosynthesis pathway as in Rhodobacter sphaeroides and R. capsulatus, but also in the spirilloxanthin biosynthesis pathway. Carotenoid genes implicated in the spirilloxanthin biosynthesis pathway were thus identified for the first time. Furthermore, analysis of carotenoid synthesis in the mutants gave genetic evidence that crtD and crtC genes are cotranscribed with the puf operon using the oxygen-regulated puf promoter.The photosynthetic apparatus in many purple bacteria contains three types of pigment-protein complexes. The two lightharvesting LHII 1 and LHI antenna capture light and transfer energy to the third complex, the reaction center (RC) in which charge separation occurs. The three complexes contain pigments, bacteriochlorophyll and carotenoids, which play an important role in the photosynthetic process.Carotenoids have three functions in bacterial photosynthesis. They act in photoprotection, they function as accessory light-harvesting pigments by absorbing light in the 450 -570 nm region (1, 2), and, in addition, they participate in the assembly of the light-harvesting antenna (3, 4).Biosynthetic pathways of carotenoids in some purple bacteria are now well known (5-7). Spectroscopic and chemical studies of the processes of carotenoid biosynthesis have been performed in different mutants, in particular in R. sphaeroides and R. capsulatus (8 -11). In these bacteria the end products of the biosynthetic pathway are spheroidene and spheroidenone; in other bacteria such as Rhodospirillum rubrum and Rubrivivax gelatinosus, in addition to the spheroidene pathway, another pathway leading to biosynthesis of spirilloxanthin and derivatives was described (5) (Fig. 1).The genes encoding many carotenoid biosynthetic enzymes have now been mapped (12). The arrangement of carotenoid genes was first described for R. capsulatus (13). As in R. sphaeroides, the carotenoid genes are clustered and flanked by bacteriochlorophyll genes within a 45-kb region of the chromosome (14, 15). In these bacteria, the first enzyme assigned to carotenoid biosynthesis is the geranylgeranyl-pyrophosphate synthase encoded by crtE gene (16, 17). The condensation of two geranylgeranyl pyrophosphate by an enzyme encoded by crtB lead to the synthesis of phytoene (16, 17), which is transformed to neurosporene by sequential desaturations which involved crtI (18,19). In R. sphaeroides and R. capsulatus, a ...

show abstract

“…Human genes have an average of 7-8 introns, and spliceosome assembly occurs de novo on each intron of a pre-mRNA transcript, necessitating an efficient and accurate method of intron removal (Sakharkar et al, 2005; Wahl et al, 2009). Known as the intron lariat turnover pathway, this late-stage step is critical for the release and processing of a subset of regulatory microRNAs (Okamura et al, 2007; Ouchane et al, 1995), as well as for the recycling of spliceosome-associated small nuclear ribonucleoproteins (snRNPs) (Hirose et al, 2003). In the absence of efficient lariat processing, retention of snRNPs in lariat-containing, late-stage splicing complexes has been reported to reduce the efficiency of subsequent spliceosome assembly (Han et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

A condensate forming tether for lariat debranching enzyme is defective in non-photosensitive trichothiodystrophy

Townley¹,

Buerer

Bacolla

et al. 2022

Preprint

View full text Add to dashboard Cite

The pre-mRNA life cycle requires intron processing; yet, how intron processing defects influence splicing and gene expression is unclear. Here, we find TTDN1, which is frequently mutated in non-photosensitive trichothiodystrophy (NP-TTD), functionally links intron lariat processing to the spliceosome. The conserved TTDN1 C-terminal region directly binds lariat debranching enzyme DBR1, while its N-terminal intrinsically disordered region (IDR) binds the intron binding complex (IBC). The IDR forms condensates in vitro and is needed for IBC interaction. TTDN1 loss causes significant intron lariat accumulation, as well as splicing and gene expression defects, mirroring phenotypes observed in NP-TTD patient cells. Ttdn1-/- mice recapitulate intron processing defects and neurodevelopmental phenotypes seen in NP-TTD. A DBR1-IDR fusion recruits DBR1 to the IBC and circumvents the requirement for TTDN1, suggesting this tethering role as the major molecular function for TTDN1. Collectively, our findings unveil key functional connections between lariat processing, splicing outcomes, and NP-TTD molecular pathology.

show abstract

A new mutation in the pufL gene responsible for the terbutryn resistance phenotype in Rubrivivax gelatinosus

Cited by 22 publications

References 22 publications

Interaction Site for Soluble Cytochromes on the Tetraheme Cytochrome Subunit Bound to the Bacterial Photosynthetic Reaction Center Mapped by Site-Directed Mutagenesis

Interaction Site for Soluble Cytochromes on the Tetraheme Cytochrome Subunit Bound to the Bacterial Photosynthetic Reaction Center Mapped by Site-Directed Mutagenesis

Pleiotropic Effects of puf Interposon Mutagenesis on Carotenoid Biosynthesis in Rubrivivax gelatinosus

A condensate forming tether for lariat debranching enzyme is defective in non-photosensitive trichothiodystrophy

Contact Info

Product

Resources

About