Lactobacillus leichmanii

Lactobacillus leichmanii ribonucleotide reductase has a molecular weight of 76 000, with a single polypeptide chain of about 690 amino acids. The large size of the apoenzyme probably reflects the need for it to have sites to interact with the coenzyme, a dithiol, a substrate and allosteric effectors. A transient radical species was observed during catalysis. 

D-Lactate Dehydrogenase Origin Lactobacillus leichmanii Fluka... 

Class II RNRs are found in bacteria [16-18] and archaea [19]. They have the ability to work both aerobically and anaerobically and, as a consequence, were found in aerobes, facultative or strict anaerobes. What characterizes a class II RNR is the requirement for adenosylcobalamin as a cofactor. It has been recently shown, in the case of the RNR from Lactobacillus leichmanii that, during catalysis, protein-bound AdoCbl reacts with a conserved cysteine residue of the active site, leading... 

Deoxy-2-thiouridine has been prepared using immobilized W-deoxyribosyl transferase from Lactobacillus leichmanii, whilst radical deoxygenation was used to prepare 2 -deoxy-3-isoadenosine (38), which was converted into the two regioisomeric dinucleoside monophosphates with thymidine. ... 

Lactobacillus leichmanii, they are similar to B12 and the cobaloximes inasmuch as the central cobalt atom may pass readily between the oxidation states (i), (ii), and (iii) the metal-carbon axial position is also stabilized. ... 

The reductase from Lactobacillus leichmanii (RNR-Ll) belongs to the class II RNRs, which make use of adenosyl-cobamides to initiate the radical reac-... 

Ribonucleotide Reductase. The ribonucleotide reductases catalyze the reduction of ribonucleoside-diphosphates (or triphosphates) to the corresponding 2 -deoxyribonucleoside-diphosphates (or triphosphates), processes of preeminent importance for the biosynthesis of DNA (see Table 2, entry 4) (65,86). A variety of metal-containing cofactors have been discovered in the ribonucleotide reductases investigated to date (eg, a binuclear iron center in the mammalian and in the E. coli ribonucleoside diphosphate reductase) and the oxidation of two protein thiols to a disulfide unit is indicated as the direct source of the two reduction equivalents. The reductase from Lactobacillus leichmanii employs coenzyme B12 as cofactor in its (normal) base-on form and acts on purine- or pyrimidine-based ribonucleoside-triphosphates. Its crystal structure reveals not only the arrangement of the bound corrinoid cofactor, but also how the enzyme is... 

The ribonucleotide reductase of Lactobacillus leichmanii catalyses the rapid conversion of enzyme-bound coenzyme B12 to an intermediate which has an absorption spectrum in the visible and u.v. like that of cob(ii)alamin (Biar)- Coffman et al. have recently analysed the e.s.r. spectrum of this intermediate and suggest that it contains low-spin cobalt(ii) with strongly distorted six-fold co-ordination. 

The iV-deoxyribosyltransferase of Lactobacillus leichmanii has been used to make the 2 5 -dideoxynucleoside (53) by transfer of the sugar unit from 5 -deoxythymidine, ... 

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