Dodecins: A Family of Lumichrome Binding Proteins

Grininger, Martin; Zeth, Kornelius; Oesterhelt, Dieter

doi:10.1016/j.jmb.2005.12.072

Cited by 51 publications

(77 citation statements)

References 59 publications

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“…Sample Preparation-The dodecin proteins are prepared as described by Grininger et al (5). Wild-type and mutant dodecin from H. salinarum with different flavin cofactors and free riboflavin were measured in 20 mM Tris buffer, pH 7.5, with 1 M NaCl and 5 mM MgCl 2 .…”

Section: Methodsmentioning

confidence: 99%

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Ultrafast Excited-state Deactivation of Flavins Bound to Dodecin

Staudt

Oesterhelt

Grininger

et al. 2012

Journal of Biological Chemistry

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Background: Dodecin prevents riboflavin from autodegradation and exerting photo-induced cellular stress. Results: Ultrafast depopulation of excited states and ground state recovery is observed by transient spectroscopy. Conclusion: Ultrafast electron transfer in combination with proton transfer is responsible for deactivation of flavin excited states. Significance: A comprehensive study of parameters in the binding pocket affecting the riboflavin quenching mechanism is given.

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Section: Methodsmentioning

confidence: 99%

“…Structures revealed a dodecameric fold, providing six identical binding pockets, which each enables binding of two antiparallel arranged flavins between two tryptophan residues building an aromatic tetrade arrangement ( Fig. 1A) (1)(2)(3)(4)(5)(6)(7).…”

mentioning

confidence: 99%

Ultrafast Excited-state Deactivation of Flavins Bound to Dodecin

Staudt

Oesterhelt

Grininger

et al. 2012

Journal of Biological Chemistry

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“…Avian eggs contain RF, FMN, FAD, and RF-binding protein (RBP), which are required for the active transport of RF into the egg and storage of the RF needed later in development (523,535). Archaea also contain RFbinding proteins (dodecins), also known as lumichrome-binding proteins, that are involved in the regulation of flavin homeostasis (157,158).…”

Section: Biological Role Of Flavinsmentioning

confidence: 99%

Genetic Control of Biosynthesis and Transport of Riboflavin and Flavin Nucleotides and Construction of Robust Biotechnological Producers

Abbas

Sibirny

2011

Microbiol Mol Biol Rev

309

264

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SUMMARY Riboflavin [7,8-dimethyl-10-(1′- d -ribityl)isoalloxazine, vitamin B 2 ] is an obligatory component of human and animal diets, as it serves as the precursor of flavin coenzymes, flavin mononucleotide, and flavin adenine dinucleotide, which are involved in oxidative metabolism and other processes. Commercially produced riboflavin is used in agriculture, medicine, and the food industry. Riboflavin synthesis starts from GTP and ribulose-5-phosphate and proceeds through pyrimidine and pteridine intermediates. Flavin nucleotides are synthesized in two consecutive reactions from riboflavin. Some microorganisms and all animal cells are capable of riboflavin uptake, whereas many microorganisms have distinct systems for riboflavin excretion to the medium. Regulation of riboflavin synthesis in bacteria occurs by repression at the transcriptional level by flavin mononucleotide, which binds to nascent noncoding mRNA and blocks further transcription (named the riboswitch). In flavinogenic molds, riboflavin overproduction starts at the stationary phase and is accompanied by derepression of enzymes involved in riboflavin synthesis, sporulation, and mycelial lysis. In flavinogenic yeasts, transcriptional repression of riboflavin synthesis is exerted by iron ions and not by flavins. The putative transcription factor encoded by SEF1 is somehow involved in this regulation. Most commercial riboflavin is currently produced or was produced earlier by microbial synthesis using special selected strains of Bacillus subtilis , Ashbya gossypii , and Candida famata . Whereas earlier RF overproducers were isolated by classical selection, current producers of riboflavin and flavin nucleotides have been developed using modern approaches of metabolic engineering that involve overexpression of structural and regulatory genes of the RF biosynthetic pathway as well as genes involved in the overproduction of the purine precursor of riboflavin, GTP.

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“…Flavins are also known to act as chromophores in photoreceptors, such as the plant blue light sensors cryptochrome and phototropin (reviewed in reference 3). Moreover, flavins are the ligands of dodecin, a recently identified flavoprotein that has the highest binding affinity to lumichrome, a lightinduced degradation product of riboflavin with an alloxazine ring structure lacking a ribityl side chain (13,48).…”

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confidence: 99%

Characterization of Riboflavin (Vitamin B₂) Transport Proteins fromBacillus subtilisandCorynebacterium glutamicum

Vogl

Grill

Schilling³

et al. 2007

J Bacteriol

102

139

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Riboflavin (vitamin B 2 ) is the direct precursor of the flavin cofactors flavin mononucleotide and flavin adenine dinucleotide, essential components of cellular biochemistry. In this work we investigated the unrelated proteins YpaA from Bacillus subtilis and PnuX from Corynebacterium glutamicum for a role in riboflavin uptake. Based on the regulation of the corresponding genes by a riboswitch mechanism, both proteins have been predicted to be involved in flavin metabolism. Moreover, their primary structures suggested that these proteins integrate into the cytoplasmic membrane. We provide experimental evidence that YpaA is a plasma membrane protein with five transmembrane domains and a cytoplasmic C terminus. In B. subtilis, riboflavin uptake was increased when ypaA was overexpressed and abolished when ypaA was deleted. Riboflavin uptake activity and the abundance of the YpaA protein were also increased when riboflavin auxotrophic mutants were grown in limiting amounts of riboflavin. YpaA-mediated riboflavin uptake was sensitive to protonophors and reduced in the absence of glucose, demonstrating that the protein requires metabolic energy for substrate translocation.In addition, we demonstrate that PnuX from C. glutamicum also is a riboflavin transporter. Transport by PnuX was not energy dependent and had high apparent affinity for riboflavin (K m 11 M). Roseoflavin, a toxic riboflavin analog, appears to be a substrate of PnuX and YpaA. We propose to designate the gene names ribU for ypaA and ribM for pnuX to reflect that the encoded proteins function in riboflavin uptake and that the genes have different phylogenetic origins.Riboflavin consists of a ribityl side chain linked to an aromatic isoalloxazine ring structure. It is the precursor of the cofactors flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), which both are essential components of cellular metabolism. Riboflavin is phosphorylated to give FMN by flavokinase (EC 2.7.1.26), and FMN is subsequently converted to FAD by FAD synthetase (EC 2.7.7.2). Whereas free riboflavin does not have biological activity, the mostly noncovalently bound flavin cofactors FMN and FAD are the active groups of a large number of flavoproteins. These are involved in a wide range of redox reactions and catalyze the dehydrogenation of metabolites, one-and two-electron transfer reactions from and to redox centers, and hydroxylation reactions (9). Flavins are also known to act as chromophores in photoreceptors, such as the plant blue light sensors cryptochrome and phototropin (reviewed in reference 3). Moreover, flavins are the ligands of dodecin, a recently identified flavoprotein that has the highest binding affinity to lumichrome, a lightinduced degradation product of riboflavin with an alloxazine ring structure lacking a ribityl side chain (13, 48).Whereas vertebrates can generate FMN and FAD from riboflavin, they lack the enzymes to synthesize riboflavin, making this compound a vitamin (vitamin B 2 ). In contrast, plants and most microorganisms are capable of ...

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Dodecins: A Family of Lumichrome Binding Proteins

Cited by 51 publications

References 59 publications

Ultrafast Excited-state Deactivation of Flavins Bound to Dodecin

Ultrafast Excited-state Deactivation of Flavins Bound to Dodecin

Genetic Control of Biosynthesis and Transport of Riboflavin and Flavin Nucleotides and Construction of Robust Biotechnological Producers

Characterization of Riboflavin (Vitamin B₂) Transport Proteins fromBacillus subtilisandCorynebacterium glutamicum

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Dodecins: A Family of Lumichrome Binding Proteins

Cited by 51 publications

References 59 publications

Ultrafast Excited-state Deactivation of Flavins Bound to Dodecin

Ultrafast Excited-state Deactivation of Flavins Bound to Dodecin

Genetic Control of Biosynthesis and Transport of Riboflavin and Flavin Nucleotides and Construction of Robust Biotechnological Producers

Characterization of Riboflavin (Vitamin B2) Transport Proteins fromBacillus subtilisandCorynebacterium glutamicum

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Characterization of Riboflavin (Vitamin B₂) Transport Proteins fromBacillus subtilisandCorynebacterium glutamicum