Spektren und Strukturen der am Flavin‐Redoxsystem beteiligten Partikeln. Studien in der Flavinreihe IX [1]

Dudley, Kenneth H.; Ehrenberg, Anders; Hemmerich, Peter; Müller, Franz

doi:10.1002/hlca.19640470531

Cited by 210 publications

(119 citation statements)

References 24 publications

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“…This interpretation is in accord with that of ultraviolet absorption spectra [22] and 13C NMR results [3].…”

Section: Flavins In the I5-dihydro Statesupporting

confidence: 92%

“…The observed upfield shift of the signal of I5N(I) of flavin in aqueous solution as compared to that in CHCI,, is in accord with the formation of a hydrogen bond and is supported by other observations. Thus it was shown by light absorption spectrometry that protonation of flavin occurs at N(l) [22]. From this it was concluded that N(l) is the most basic atom in the oxidized flavin molecule.…”

Section: N1101mentioning

confidence: 99%

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Nuclear‐magnetic‐resonance investigation of ¹⁵N‐labeled flavins, free and bound to Megasphaera elsdenii apoflavodoxin

Franken

Rüterjans

Müller

1984

European Journal of Biochemistry

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Flavin derivatives, enriched with 5N (w 95 %) at the four nitrogen atoms of the isoalloxazine ring, have been investigated in the oxidized and the two-electron reduced state by the 5N nuclear magnetic resonance technique. The measurements were conducted with aqueous and chloroform solutions of flavin. A comparison of the chemical shifts of the N(l) and N(5) atoms of oxidized flavin in the two solvents revealed that these atoms are sensitive indicators for possible hydrogen-bridge formation to these atoms. The N(5) atom of oxidized flavin resonates at low field and shifts about 300 ppm upfield upon reduction.A pK, of 6.8 was determined from pH-dependent 15N NMR measurements of the two-electron reduced flavin molecule. In addition it is also shown that reduced flavin in aqueous solution possesses a more coplanar structure than in chloroform solution. The 'N chemical shifts of flavin bound to Megasphaera elsdenii apoflavodoxin indicate that various hydrogen bridges are formed between the prosthetic group and the apoprotein. Especially the N(l) atom of the prosthetic group in the oxidized state seems to form a strong hydrogen bond with the apoprotein. In the reduced state the prosthetic group is bound in the anionic form and possesses an almost coplanar structure. These results are in agreement with published crystallographic data on the related flavodoxin from Clostridium MP.Where possible 15N-'H, 15N-15N and 13C-15N coupling constants were determined. Some of the coupling constants are useful parameters for the elucidation of the planarity of free and protein-bound flavin and for the evaluation of the interaction between flavin and apoprotein.Spin-lattice relaxation measurements show that the relaxation of the 5N(3)H group of flavin is predominantly determined by dipole-dipole interaction. The calculated rotational correlation times of flavin in two different solvents were determined and are in good agreement with published results.Flavodoxins are proteins of small molecular mass (= 15000 Da) functioning as electron carriers in low-potential oxidation-reduction reactions [l]. The prosthetic group of flavodoxins is riboflavin 5'-phosphate (FMN). The flavodoxins contain no metal ions but are able to replace the ironsulfur proteins ferredoxins in biological reactions.The three-dimensional structure of the Clostridium MP flavodoxin is known [l]. The crystal structure of the more easily available, related flavodoxin from Megasphaera elsdenii is not known, but its physical and chemical properties have been studied in detail [l]. The NMR technique is a valuable tool to study the specific interaction between the apoprotein and the prosthetic group. It has been postulated that such specific interactions are responsible for the specific biological reaction catalyzed by a particular flavoprotein [2]. In this respect the 'H and 13C NMR technique has already been applied succesfully to M . elsdenii flavodoxin [3, 41.Abbreviations. FMN, riboflavin 5'-phosphate; FMNH, and FMNH-, neutral and anionic l,Sdihydro-FMN, respectively; ...

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“…This interpretation is in accord with that of ultraviolet absorption spectra [22] and 13C NMR results [3].…”

Section: Flavins In the I5-dihydro Statesupporting

confidence: 92%

Section: N1101mentioning

confidence: 99%

Nuclear‐magnetic‐resonance investigation of ¹⁵N‐labeled flavins, free and bound to Megasphaera elsdenii apoflavodoxin

Franken

Rüterjans

Müller

1984

European Journal of Biochemistry

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“…of 0.9 occurs predominantly at the 6-amino function (Figure 3), but the complexity of the spectrum indicates that other tautomers possibly exist as well. In strong acid, the dicationic form must be present, as shown by the single absorption band at 393 nm, which is characteristic of isoalloxazines carrying a positive charge on the nucleus and in which an exocyclic conjugation is absent (Dudley et al, 1964). Acylation of the amino group of 6-amino flavins gives rise -..::::.-- …”

Section: Resultsmentioning

confidence: 99%

Chemical synthesis and some properties of 6-substituted flavins

Ghisla¹,

Kenney²,

Knappe³

et al. 1980

Biochemistry

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“…Structure C is unlikely because it would constitute an alkylated reduced flavin, a species with A-around 310 nm (Dudley et al, 1964). Furthermore, in compounds such as C and D, the N(1)-H pK should be in the region 6-7, the same as with reduced flavins (Ghisla et al, 1974), while a pK of approximately 3.1 is found for pink flavin (cf.…”

Section: Resultsmentioning

confidence: 99%

Structure of the flavin adduct formed in the suicide reaction of .alpha.-hydroxybutynoate with D-lactate dehydrogenase

Ghisla¹,

Olson²,

Massey³

et al. 1979

Biochemistry

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The Zn-dependent flavoenzyme D-lactate dehydrogenase from Megasphaera elsdenii is irreversibly inactivated by the D form of the suicide substrate 2-hydroxy-3-butynoic acid. The process of inactivation involves formation of a new pink chromophore, which can be released in intact form from the protein and which was purified to homogeneity by affinity chromatography. Inactivation involves covalent addition of the suicide substrate to the flavin coenzyme. The optical spectra indicate an elongation of the flavin chromophore, and the chemical reactivity suggests a derivative of reduced flavin. The structure of this adduct was deduced from Fourier transform NMR, from the chemical properties, and from comparison with appropriate models, which were synthesized chemically. This structure involves the covalent linkage of the acetylenic inhibitor to positions N(5) and C(6) of the flavin coenzyme via carbon atoms 2 and 4 of the in-

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Spektren und Strukturen der am Flavin‐Redoxsystem beteiligten Partikeln. Studien in der Flavinreihe IX [1]

Cited by 210 publications

References 24 publications

Nuclear‐magnetic‐resonance investigation of ¹⁵N‐labeled flavins, free and bound to Megasphaera elsdenii apoflavodoxin

Nuclear‐magnetic‐resonance investigation of ¹⁵N‐labeled flavins, free and bound to Megasphaera elsdenii apoflavodoxin

Chemical synthesis and some properties of 6-substituted flavins

Structure of the flavin adduct formed in the suicide reaction of .alpha.-hydroxybutynoate with D-lactate dehydrogenase

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Spektren und Strukturen der am Flavin‐Redoxsystem beteiligten Partikeln. Studien in der Flavinreihe IX [1]

Cited by 210 publications

References 24 publications

Nuclear‐magnetic‐resonance investigation of 15N‐labeled flavins, free and bound to Megasphaera elsdenii apoflavodoxin

Nuclear‐magnetic‐resonance investigation of 15N‐labeled flavins, free and bound to Megasphaera elsdenii apoflavodoxin

Chemical synthesis and some properties of 6-substituted flavins

Structure of the flavin adduct formed in the suicide reaction of .alpha.-hydroxybutynoate with D-lactate dehydrogenase

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Nuclear‐magnetic‐resonance investigation of ¹⁵N‐labeled flavins, free and bound to Megasphaera elsdenii apoflavodoxin

Nuclear‐magnetic‐resonance investigation of ¹⁵N‐labeled flavins, free and bound to Megasphaera elsdenii apoflavodoxin