NMR studies of flavoproteins

Rüterjans, Heinz; Fleischmann, Garrit; Knauf, Martin; Löhr, Frank; Blümel, Markus; Lederer, Florence; Mayhew, Stephen G.; Müller, Francis

doi:10.1042/bst0240116

Cited by 11 publications

(12 citation statements)

References 8 publications

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“…6). The functional consequences of this bent conformation is that the N atom at the 5 position of the flavin ring is in a configuration closer to sp 3 rather than to sp 2 as shown by previous 15 N and 13 C NMR data on other flavoenzymes and on model flavin systems [27]. This results in a higher electron density at N(5) and lowered electron density at the C4a position of the flavin ring.…”

Section: Proposed Mechanism Of C-h Bond Cleavage In Mao Catalysismentioning

confidence: 66%

Structural insights into the mechanism of amine oxidation by monoamine oxidases A and B

Edmondson¹,

Binda²,

Mattevi³

2007

Archives of Biochemistry and Biophysics

184

144

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Due to their pharmacological importance in the oxidation of amine neurotransmitters, the membrane-bound flavoenzymes monoamine oxidase A and monoamine oxidase B have attracted numerous investigations and, as a result, two different mechanisms; the single electron transfer and the polar nucleophilic mechanisms, have been proposed to describe their catalytic mechanisms. This review compiles the recently available structural data on both enzymes with available mechanistic data as well as current NMR data on flavin systems to provide an integration of the approaches. These conclusions support the proposal that a polar nucleophilic mechanism for amine oxidation is the most consistent mechanistic scheme as compared with the single electron transfer mechanism.

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Section: Proposed Mechanism Of C-h Bond Cleavage In Mao Catalysismentioning

confidence: 66%

Structural insights into the mechanism of amine oxidation by monoamine oxidases A and B

Edmondson¹,

Binda²,

Mattevi³

2007

Archives of Biochemistry and Biophysics

184

144

View full text Add to dashboard Cite

show abstract

“…The changes observed upon reduction of N5 also agree well with those predicted by theory and calculations. It is gratifying to discover that not only the previously-studied isotropic shifts, 19,[30][31][32][33] but even more so, the very different chemical shift principal values measured here, reflect extreme and distinct electronic properties for N5 and N1.…”

Section: Discussionmentioning

confidence: 77%

“…Flavin vibrational frequencies can be interpreted in terms of more local effects, [26][27][28] but possibly the most site-specific probes available so far are EPR hyperfine couplings for the semiquinone states 29 and NMR chemical shifts for the diamagnetic states. [30][31][32][33] NMR chemical shifts and J-couplings have been interpreted in elegant detail in terms of π electron density, sp 2 /sp 3 character and hydrogen bonding at various sites, leading to valuable insights into the polarization of the flavin ring system, its protonation state, hydrogen bonding and pyramidalization at N10 and N5. [30][31][32]3435 However, the isotropic shifts measured in solution represent the average of all the effects on total electron density.…”

Section: Introductionmentioning

confidence: 99%

¹⁵N Solid-State NMR Provides a Sensitive Probe of Oxidized Flavin Reactive Sites

et al. 2006

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Flavins are central to the reactivity of a wide variety of enzymes and electron transport proteins. There is great interest in understanding the basis for the different reactivities displayed by flavins in different protein contexts. We propose solid-state nuclear magnetic resonance (SS-NMR) as a tool for directly observing reactive positions of the flavin ring and thereby obtaining information on their frontier orbitals. We now report the SS-NMR signals of the redox-active nitrogens N1 and N5, as well as that of N3. The chemical shift tensor of N5 is over 720 ppm wide, in accordance with the predictions of theory and our calculations. The signal of N3 can be distinguished on the basis of coupling to 1H absent for N1 and N5, as well as the shift tensor span of only 170 ppm, consistent with N3's lower aromaticity and lack of a nonbonding lone pair. The isotropic shifts and spans of N5 and N1 reflect two opposite extremes of the chemical shift range for "pyridine-type" N's, consistent with their electrophilic and nucleophilic chemical reactivities, respectively. Upon flavin reduction, N5's chemical shift tensor contracts dramatically to a span of less than 110 ppm, and the isotropic chemical shift changes by approximately 300 ppm. Both are consistent with loss of N5's nonbonding lone pair and decreased aromaticity, and illustrate the responsiveness of the 15N chemical shift principal values to electronic structure. Thus. 15N chemical shift principal values promise to be valuable tools for understanding electronic differences that underlie variations in flavin reactivity, as well as the reactivities of other heterocyclic cofactors.

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“…Solution-state NMR has been used extensively to infer bond order, the existence and strength of H-bonding, and more. 14,24–26 Indeed, the isotropic chemical shifts (δ iso s) 1 measured in solution for individual flavin ring C and N atoms vary by over more than 10 and 40 ppm respectively, among flavins in different environments. 24 …”

Section: Introductionmentioning

confidence: 99%

¹⁵N Solid-State NMR as a Probe of Flavin H-Bonding

et al. 2011

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Flavins mediate a wide variety of different chemical reactions in biology. To learn how one cofactor can be made to execute different reactions in different enzymes, we are developing solid-state NMR (SSNMR) to probe the flavin electronic structure, via the 15N chemical shift tensor principal values (δii). We find that SSNMR has superior responsiveness to H-bonds, compared to solution NMR. H-bonding to a model of the flavodoxin active site produced an increase of 10 ppm in the δ11 of N5 although none of the H-bonds directly engage N5, and solution NMR detected only a 4 ppm increase in the isotropic chemical shift (δiso). Moreover SSNMR responded differently to different H-bonding environments as H-bonding with water caused δ11 to decrease by 6 ppm whereas δiso increased by less than 1 ppm. Our density functional theoretical (DFT) calculations reproduce the observations, validating the use of computed electronic structures to understand how H-bonds modulate the flavin’s reactivity.

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NMR studies of flavoproteins

Cited by 11 publications

References 8 publications

Structural insights into the mechanism of amine oxidation by monoamine oxidases A and B

Structural insights into the mechanism of amine oxidation by monoamine oxidases A and B

¹⁵N Solid-State NMR Provides a Sensitive Probe of Oxidized Flavin Reactive Sites

¹⁵N Solid-State NMR as a Probe of Flavin H-Bonding

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NMR studies of flavoproteins

Cited by 11 publications

References 8 publications

Structural insights into the mechanism of amine oxidation by monoamine oxidases A and B

Structural insights into the mechanism of amine oxidation by monoamine oxidases A and B

15N Solid-State NMR Provides a Sensitive Probe of Oxidized Flavin Reactive Sites

15N Solid-State NMR as a Probe of Flavin H-Bonding

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Product

Resources

About

¹⁵N Solid-State NMR Provides a Sensitive Probe of Oxidized Flavin Reactive Sites

¹⁵N Solid-State NMR as a Probe of Flavin H-Bonding