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Adenosylcobalamin

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https://www.readbyqxmd.com/read/28634850/novel-vitamin-b12-producing-enterococcus-spp-and-preliminary-in-vitro-evaluation-of-probiotic-potentials
#1
Ping Li, Qing Gu, Yuejiao Wang, Yue Yu, Lanlan Yang, Jieyan V Chen
Vitamin B12 is an essential nutrient required for crucial metabolic processes in humans. Vitamin B12-producing lactic acid bacteria (LAB) have been attracting increased attentions currently because of the generally recognized as safe (GRAS) status. Most of recent studies focused on Lactobacillus, and little is known about B12-producing Enterococcus. In the present study, five Enterococcus strains isolated from infant feces were identified as vitamin B12 producers. Among them, Enterococcus faecium LZ86 had the highest B12 production (499...
June 20, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28551266/characterization-of-extracellular-vitamin-b12-producing-lactobacillus-plantarum-strains-and-assessment-of-the-probiotic-potentials
#2
Ping Li, Qing Gu, Lanlan Yang, Yue Yu, Yuejiao Wang
We investigated extracellular vitamin B12-producing Lactobacillus strains and their characteristics in tolerance to environmental stresses, gastric acid and bile salts. Two isolates, Lactobacillus plantarum LZ95 and CY2, showed high extracellular B12 production, 98±15μg/L and 60±9μg/L respectively. Extracellular B12 from LZ95 were identified as adenosylcobalamin and methylcobalamin using a combination of solid phase extraction and reverse-phase HPLC, while that from CY2 was adenosylcobalamin. Both strains grew under environmental stresses, and LZ95 exhibited better tolerance to low temperature and high ethanol concentration...
November 1, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28533376/b12-dependent-photoresponsive-protein-hydrogels-for-controlled-stem-cell-protein-release
#3
Ri Wang, Zhongguang Yang, Jiren Luo, I-Ming Hsing, Fei Sun
Thanks to the precise control over their structural and functional properties, genetically engineered protein-based hydrogels have emerged as a promising candidate for biomedical applications. Given the growing demand for creating stimuli-responsive "smart" hydrogels, here we show the synthesis of entirely protein-based photoresponsive hydrogels by covalently polymerizing the adenosylcobalamin (AdoB12)-dependent photoreceptor C-terminal adenosylcobalamin binding domain (CarHC) proteins using genetically encoded SpyTag-SpyCatcher chemistry under mild physiological conditions...
June 6, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28528213/optimal-electrostatic-interactions-between-substrate-and-protein-are-essential-for-radical-chemistry-in-ornithine-4-5-aminomutase
#4
Caitlyn Makins, Douglas A Whitelaw, Michael McGregor, Alix Petit, Robert G Mothersole, Kathleen E Prosser, Kirsten R Wolthers
Ornithine 4,5-aminomutase (OAM) from Clostridium sticklandii is an adenosylcobalamin (AdoCbl) and pyridoxal 5'-phosphate (PLP)-dependent enzyme that catalyzes a 1,2-amino shift, interconverting d-ornithine and 2S, 4R-diaminopentanoate. The reaction occurs via a radical-based mechanism whereby a PLP-bound substrate radical undergoes intramolecular isomerization via an azacyclopropylcarbinyl radical intermediate. Herein, we investigated the catalytic role of active site residues that form non-covalent interactions with PLP and/or substrate, d-ornithine...
August 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28497574/protein-destabilization-and-loss-of-protein-protein-interaction-are-fundamental-mechanisms-in-cbla-type-methylmalonic-aciduria
#5
Tanja Plessl, Céline Bürer, Seraina Lutz, Wyatt W Yue, Matthias R Baumgartner, D Sean Froese
Mutations in the human MMAA gene cause the metabolic disorder cblA-type methylmalonic aciduria (MMA), although knowledge of the mechanism of dysfunction remains lacking. MMAA regulates the incorporation of the cofactor adenosylcobalamin (AdoCbl), generated from the MMAB adenosyltransferase, into the destination enzyme methylmalonyl-CoA mutase (MUT). This function of MMAA depends on its GTPase activity, which is stimulated by an interaction with MUT. Here, we present 67 new patients with cblA-type MMA, identifying 19 novel mutations...
August 2017: Human Mutation
https://www.readbyqxmd.com/read/28483920/cobalamin-riboswitches-exhibit-a-broad-range-of-ability-to-discriminate-between-methylcobalamin-and-adenosylcobalamin
#6
COMPARATIVE STUDY
Jacob T Polaski, Samantha M Webster, James E Johnson, Robert T Batey
Riboswitches are a widely distributed class of regulatory RNAs in bacteria that modulate gene expression via small-molecule-induced conformational changes. Generally, these RNA elements are grouped into classes based upon conserved primary and secondary structure and their cognate effector molecule. Although this approach has been very successful in identifying new riboswitch families and defining their distributions, small sequence differences between structurally related RNAs can alter their ligand selectivity and regulatory behavior...
July 14, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28223907/comparative-bioavailability-and-utilization-of-particular-forms-of-b12-supplements-with-potential-to-mitigate-b12-related-genetic-polymorphisms
#7
REVIEW
Cristiana Paul, David M Brady
CONTEXT: Three natural forms of vitamin B12 are commercially available: methylcobalamin (MeCbl), adenosylcobalamin (AdCbl), and hydroxycobalamin (OHCbl), all of which have been shown in clinical studies to improve vitamin B12 status. They are bioidentical to the B12 forms occurring in human physiology and animal foods. In contrast, cyanocobalamin (CNCbl), a synthetic B12 compound used for food fortification and in some supplements, occurs only in trace amounts in human tissues as a result of cyanide intake from smoking or other sources...
February 2017: Integrative Medicine
https://www.readbyqxmd.com/read/28167430/vitamin-b12-in-the-spotlight-again
#8
REVIEW
Jennifer Bridwell-Rabb, Catherine L Drennan
The ability of cobalamin to coordinate different upper axial ligands gives rise to a diversity of reactivity. Traditionally, adenosylcobalamin is associated with radical-based rearrangements, and methylcobalamin with methyl cation transfers. Recently, however, a new role for adenosylcobalamin has been discovered as a light sensor, and a methylcobalamin-dependent enzyme has been identified that is suggested to transfer a methyl anion. Additionally, recent studies have provided a wealth of new information about a third class of cobalamin-dependent enzymes that do not appear to use an upper ligand...
April 2017: Current Opinion in Chemical Biology
https://www.readbyqxmd.com/read/28045498/spectroscopic-studies-of-the-eutt-adenosyltransferase-from-salmonella-enterica-evidence-of-a-tetrahedrally-coordinated-divalent-transition-metal-cofactor-with-cysteine-ligation
#9
Ivan G Pallares, Theodore C Moore, Jorge C Escalante-Semerena, Thomas C Brunold
The EutT enzyme from Salmonella enterica, a member of the family of ATP:cobalt(I) corrinoid adenosyltransferase (ACAT) enzymes, requires a divalent transition metal ion for catalysis, with Fe(II) yielding the highest activity. EutT contains a unique cysteine-rich HX11CCX2C(83) motif (where H and the last C occupy the 67th and 83rd positions, respectively, in the amino acid sequence) not found in other ACATs and employs an unprecedented mechanism for the formation of adenosylcobalamin. Recent kinetic and spectroscopic studies of this enzyme revealed that residues in the HX11CCX2C(83) motif are required for the tight binding of the divalent metal ion and are critical for the formation of a four-coordinate (4c) cob(II)alamin [Co(II)Cbl] intermediate in the catalytic cycle...
January 17, 2017: Biochemistry
https://www.readbyqxmd.com/read/27858373/vitamin-b12-administration-by-subcutaneous-catheter-device-in-a-cobalamin-a-cbla-patient
#10
E Maines, G Morandi, G Gugelmo, F Ion-Popa, N Campostrini, A Pasini, M Vincenzi, F Teofoli, M Camilot, A Bordugo
Cobalamin A deficiency (cblA) is an inherited disorder of intracellular cobalamin metabolism, caused by impaired 5'-deoxy-adenosylcobalamin (AdoCbl) synthesis. Hydroxocobalamin (OHCbl) is the cornerstone of cblA treatment because vitamin B12 may completely restore AdoCbl deficiency. Parenteral administration, intravenous, subcutaneous or intramuscular, is generally required to achieve effect. Daily injections represent a problem for the parents and the caregivers, and this may lead to poor compliance and scarce adherence to the long-term treatment...
November 18, 2016: JIMD Reports
https://www.readbyqxmd.com/read/27748967/salmonella-enterica-synthesizes-5-6-dimethylbenzimidazolyl-dmb-%C3%AE-riboside-why-some-firmicutes-do-not-require-the-canonical-dmb-activation-system-to-synthesize-adenosylcobalamin
#11
Theodoric A Mattes, Jorge C Escalante-Semerena
5,6-Dimethylbenzimidazolyl-(DMB)-α-ribotide [α-ribazole-5'-phosphate (α-RP)] is an intermediate in the biosynthesis of adenosylcobalamin (AdoCbl) in many prokaryotes. In such microbes, α-RP is synthesized by nicotinate mononucleotide (NaMN):DMB phosphoribosyltransferases (CobT in Salmonella enterica), in a reaction that is considered to be the canonical step for the activation of the base of the nucleotide present in adenosylcobamides. Some Firmicutes lack CobT-type enzymes but have a two-protein system comprised of a transporter (i...
January 2017: Molecular Microbiology
https://www.readbyqxmd.com/read/27693961/molecular-and-cellular-effects-of-vitamin-b12-forms-on-human-trophoblast-cells-in-presence-of-excessive-folate
#12
COMPARATIVE STUDY
Tejas Shah, Kalpana Joshi, Sanjay Mishra, Suhas Otiv, Vijay Kumbar
Folic acid (FA) and iron are essential supplements during pregnancy. Similarly effects of vitamin B12 (B12) inadequacy and high folate and low B12 status, on pregnancy outcome are available. However there are no mandatory recommendations for B12. There are many forms of B12 viz. Cyanocobalamin (Cbl), Methylcobalamin (MeCbl), Adenosylcobalamin (AdCbl), and Hydroxycobalamin (HCbl) though there is limited consensus on which form has better efficacy. In the present study we have determined effect of various forms of B12 in the presence of two FA concentrations namely normal physiological (20ng/mL; NPFA) and supra-physiological (2000ng/mL; SPFA) concentration to mimic real time situation where FA is in excess due to supplementation...
December 2016: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
https://www.readbyqxmd.com/read/27383231/resonance-raman-spectroscopic-study-of-the-interaction-between-co-ii-rrinoids-and-the-atp-corrinoid-adenosyltransferase-pduo-from-lactobacillus-reuteri
#13
Kiyoung Park, Paola E Mera, Jorge C Escalante-Semerena, Thomas C Brunold
The human-type ATP:corrinoid adenosyltransferase PduO from Lactobacillus reuteri (LrPduO) catalyzes the adenosylation of Co(II)rrinoids to generate adenosylcobalamin (AdoCbl) or adenosylcobinamide (AdoCbi(+)). This process requires the formation of "supernucleophilic" Co(I)rrinoid intermediates in the enzyme active site which are properly positioned to abstract the adeonsyl moiety from co-substrate ATP. Previous magnetic circular dichroism (MCD) spectroscopic and X-ray crystallographic analyses revealed that LrPduO achieves the thermodynamically challenging reduction of Co(II)rrinoids by displacing the axial ligand with a non-coordinating phenylalanine residue to produce a four-coordinate species...
September 2016: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/27356617/mechanism-of-co-c-photodissociation-in-adenosylcobalamin
#14
Brady D Garabato, Piotr Lodowski, Maria Jaworska, Pawel M Kozlowski
A mechanism of Co-C bond photodissociation in the base-on form of adenosylcobalamin (AdoCbl) was investigated by time-dependent density functional theory (TD-DFT). The key mechanistic step involves singlet radical pair (RP) generation from the first electronically excited state (S1). To connect TD-DFT calculations with ultra-fast excited state dynamics, the potential energy surface (PES) of the S1 state was constructed using Co-C and Co-NIm axial coordinates. The S1 PES can be characterized by two minima separated by a seam resulting from the crossing of two surfaces, of metal-to-ligand charge transfer (MLCT) character near the minimum, and a shallow ligand field (LF) surface at elongated axial bond distances...
July 28, 2016: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/27349184/inborn-error-of-cobalamin-metabolism-associated-with-the-intracellular-accumulation-of-transcobalamin-bound-cobalamin-and-mutations-in-znf143-which-codes-for-a-transcriptional-activator
#15
Mihaela Pupavac, David Watkins, Francis Petrella, Somayyeh Fahiminiya, Alexandre Janer, Warren Cheung, Anne-Claude Gingras, Tomi Pastinen, Joseph Muenzer, Jacek Majewski, Eric A Shoubridge, David S Rosenblatt
Vitamin B12 (cobalamin, Cbl) cofactors adenosylcobalamin (AdoCbl) and methylcobalamin (MeCbl) are required for the activity of the enzymes methylmalonyl-CoA mutase (MCM) and methionine synthase (MS). Inborn errors of Cbl metabolism are rare Mendelian disorders associated with hematological and neurological manifestations, and elevations of methylmalonic acid and/or homocysteine in the blood and urine. We describe a patient whose fibroblasts had decreased functional activity of MCM and MS and decreased synthesis of AdoCbl and MeCbl (3...
September 2016: Human Mutation
https://www.readbyqxmd.com/read/27274708/the-proteome-and-lipidome-of-thermococcus-kodakarensis-across-the-stationary-phase
#16
Emma J Gagen, Marcos Y Yoshinaga, Franka Garcia Prado, Kai-Uwe Hinrichs, Michael Thomm
The majority of cells in nature probably exist in a stationary-phase-like state, due to nutrient limitation in most environments. Studies on bacteria and yeast reveal morphological and physiological changes throughout the stationary phase, which lead to an increased ability to survive prolonged nutrient limitation. However, there is little information on archaeal stationary phase responses. We investigated protein- and lipid-level changes in Thermococcus kodakarensis with extended time in the stationary phase...
2016: Archaea: An International Microbiological Journal
https://www.readbyqxmd.com/read/27169753/laboratory-assessment-of-vitamin-b12-status
#17
Dominic J Harrington
The detection and correction of vitamin B12 (B12) deficiency prevents megaloblastic anaemia and potentially irreversible neuropathy and neuropsychiatric changes. B12 status is commonly estimated using the abundance of the vitamin in serum, with ∼148 pmol/L (200 ng/L) typically set as the threshold for diagnosing deficiency. Serum B12 assays measure the sum of haptocorrin-bound and transcobalamin-bound (known as holotranscobalamin) B12 It is only holotranscobalamin that is taken up by cells to meet metabolic demand...
February 2017: Journal of Clinical Pathology
https://www.readbyqxmd.com/read/27072298/fermentative-production-of-1-propanol-from-d-glucose-l-rhamnose-and-glycerol-using-recombinant-escherichia-coli
#18
Mitsuru Matsubara, Nobuyuki Urano, Shohei Yamada, Ai Narutaki, Misaki Fujii, Michihiko Kataoka
Fermentative production of 1-propanol, which is one of the promising precursors of polypropylene production, from d-glucose, l-rhamnose and glycerol using metabolically engineered Escherichia coli was examined. To confer the ability to produce 1-propanol from 1,2-propanediol (1,2-PD) in recombinant E. coli, a part of the pdu regulon including the diol dehydratase and the propanol dehydrogenase genes together with the adenosylcobalamin (AdoCbl) regeneration enzyme genes of Klebsiella pneumoniae was cloned, and an expression vector for these genes (pRSF_pduCDEGHOQS) was constructed...
October 2016: Journal of Bioscience and Bioengineering
https://www.readbyqxmd.com/read/27057274/neuregulin-1-promotes-glutathione-dependent-neuronal-cobalamin-metabolism-by-stimulating-cysteine-uptake
#19
Yiting Zhang, Nathaniel Hodgson, Malav Trivedi, Richard Deth
Neuregulin 1 (NRG-1) is a key neurotrophic factor involved in energy homeostasis and CNS development, and impaired NRG-1 signaling is associated with neurological disorders. Cobalamin (Cbl), also known as vitamin B12, is an essential micronutrient which mammals must acquire through diet, and neurologic dysfunction is a primary clinical manifestation of Cbl deficiency. Here we show that NRG-1 stimulates synthesis of the two bioactive Cbl species adenosylcobalamin (AdoCbl) and methylcobalamin (MeCbl) in human neuroblastoma cells by both promoting conversion of inactive to active Cbl species and increasing neuronal Cbl uptake...
2016: Oxidative Medicine and Cellular Longevity
https://www.readbyqxmd.com/read/26886077/spectroscopic-studies-of-the-eutt-adenosyltransferase-from-salmonella-enterica-mechanism-of-four-coordinate-co-ii-cbl-formation
#20
Ivan G Pallares, Theodore C Moore, Jorge C Escalante-Semerena, Thomas C Brunold
EutT from Salmonella enterica is a member of a class of enzymes termed ATP:Co(I)rrinoid adenosyltransferases (ACATs), implicated in the biosynthesis of adenosylcobalamin (AdoCbl). In the presence of cosubstrate ATP, ACATs raise the Co(II)/Co(I) reduction potential of their cob(II)alamin [Co(II)Cbl] substrate by >250 mV via the formation of a unique four-coordinate (4c) Co(II)Cbl species, thereby facilitating the formation of a "supernucleophilic" cob(I)alamin intermediate required for the formation of the AdoCbl product...
March 23, 2016: Journal of the American Chemical Society
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