Mapping the interactions between flavodoxin and its physiological partners flavodoxin reductase and cobalamin-dependent methionine synthase

Hall, D A; Kooi, Craig W. Vander; Stasik, Chad N.; Stevens, Shawn Y.; Zuiderweg, Erik R. P.; Matthews, Rowena G.

doi:10.1073/pnas.171168898

Cited by 91 publications

(109 citation statements)

References 33 publications

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“…Chemical shift perturbation is the most commonly used NMR method to map protein interfaces (50,51 15 N chemical shift perturbation has been used in many cases to map protein-protein interactions (50 -52). To understand the mechanism of the IL1␣ non-classical secretion pathway at the molecular level, we solved the structures of free IL1␣ and the IL1␣-S100A13 tetrameric complex, which is potentially the key complex formed in the non-classical secretion pathway of IL1␣.…”

Section: Resultsmentioning

confidence: 99%

The IL1α-S100A13 Heterotetrameric Complex Structure

Mohan

2011

Journal of Biological Chemistry

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Interleukin 1␣ (IL1␣) plays an important role in several key biological functions, such as angiogenesis, cell proliferation, and tumor growth in several types of cancer. IL1␣ is a potent cytokine that induces a wide spectrum of immunological and inflammatory activities. The biological effects of IL1␣ are mediated through the activation of transmembrane receptors (IL1Rs) and therefore require the release of the protein into the extracellular space. IL1␣ is exported through a non-classical release pathway involving the formation of a specific multiprotein complex, which includes IL1␣ and S100A13. Because IL1␣ plays an important role in cell proliferation and angiogenesis, inhibiting the formation of the IL1␣-S100A13 complex would be an effective strategy to inhibit a wide range of cancers. To understand the molecular events in the IL1␣ release pathway, we studied the structure of the IL1␣-S100A13 tetrameric complex, which is the key complex formed during the non-classical pathway of IL1␣ release.

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Section: Resultsmentioning

confidence: 99%

The IL1α-S100A13 Heterotetrameric Complex Structure

Mohan

2011

Journal of Biological Chemistry

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“…Furthermore, both of these flavodoxin-like domains contain a positively charged lysine residue at the position equivalent to Arg 93 in MioC. The electrostatic potential at the protein surface may act in orienting the protein in protein-protein interactions (74). Therefore, a similar pattern of charge distribution between MioC and these flavodoxin-like domains may suggest similar redox partner-interacting surfaces and thus similar biological functions.…”

Section: Nmr Characterizations Of the Apo-and Holo-forms Of E Colimentioning

confidence: 99%

“…The missing residues caused by the conformational exchanges are colored in black. The figures were generated using MOLMOL (54 Since the FMN-binding site is also involved in the redox partner interaction and subsequently the electron transfer (74,84), the motional flexibility observed in this region of the holo-form of MioC may be required for redox partner recognition.…”

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confidence: 99%

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Solution Structures and Backbone Dynamics of a Flavodoxin MioC from Escherichia coli in both Apo- and Holo-forms

Zhang

et al. 2006

Journal of Biological Chemistry

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Flavodoxins play central roles in the electron transfer involving various biological processes in microorganisms. The mioC gene of Escherichia coli encodes a 16-kDa flavodoxin and locates next to the chromosomal replication initiation origin (oriC). Extensive researches have been carried out to investigate the relationship between mioC transcription and replication initiation. Recently, the MioC protein was proposed to be essential for the biotin synthase activity in vitro. Nevertheless, the exact role of MioC in biotin synthesis and its physiological function in vivo remain elusive. In order to understand the molecular basis of the biological functions of MioC and the cofactor-binding mechanisms of flavodoxins, we have determined the solution structures of both the apo-and holo-forms of E. coli MioC protein at high resolution by nuclear magnetic resonance spectroscopy. The overall structures of both forms consist of an ␣/␤ sandwich, which highly resembles the classical flavodoxin fold. However, significant diversities are observed between the two forms, especially the stabilization of the FMN-binding loops and the notable extension of secondary structures upon FMN binding. Structural comparison reveals fewer negative charged and aromatic residues near the FMN-binding site of MioC, as compared with that of flavodoxin 1 from E. coli, which may affect both the redox potentials and the redox partner interactions. Furthermore, the backbone dynamics studies reveal the conformational flexibility at different time scales for both apo-and holo-forms of MioC, which may play important roles for cofactor binding and electron transfer.Flavodoxins are small FMN-binding proteins found mainly in prokaryotes that are involved in the electron transfer chain reactions of various biological processes, including photosynthesis (1, 2), nitrate reduction (3), methionine synthesis (4 -7), biotin synthesis (8 -11), and activation of certain enzymes, such as pyruvate-formate lyase (13) and (E)-4-hydroxy-3-methylbutyl-2-enyl pyrophosphate synthase (14). It has been established by potentiometry that electrons flow from NADPH to flavodoxin reductase and then to flavodoxin, which subsequently transfers the electron to the downstream targets (15). Eukaryotes and most prokaryotes also contain proteins carrying domains homologous to flavodoxins and flavodoxin reductase in a single polypeptide chain, such as the NADPH-cytochrome P450 oxidoreductase (CPR) 2 (16, 17), nitric-oxide synthase (NOS) (18), methionine synthase reductase (19), and sulfite reductase (20,21). These domains function in a similar fashion as the flavodoxins and flavodoxin reductase proteins in prokaryotic cells. Extensive efforts have been devoted to understanding the cofactor binding, redox partner interaction, and electron transfer mechanisms of flavodoxins and flavodoxinlike domains as well as the folding and stability of these proteins (22-26). However, the detailed mechanisms are not clear yet and remain to be further elucidated.Flavodoxins are classified into the long-...

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“…The Cterminal module that binds AdoMet is an unusual helmetshaped domain with the AdoMet binding site located on the inner surface of the helmet (8). This domain also contains determinants for binding of flavodoxin (14,15).…”

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confidence: 99%

Factors modulating conformational equilibria in large modular proteins: A case study with cobalamin-dependent methionine synthase

Bandarian

Ludwig

Matthews

2003

Proc. Natl. Acad. Sci. U.S.A.

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In the course of catalysis or signaling, large multimodular proteins often undergo conformational changes that reposition the modules with respect to one another. The mechanisms that direct the reorganization of modules in these proteins are of considerable importance, but distinguishing alternate conformations is a challenge. Cobalamin-dependent methionine synthase (MetH) is a 136-kDa multimodular enzyme with a cobalamin chromophore; the color of the cobalamin reflects the conformation of the protein. The enzyme contains four modules and catalyzes three different methyl transfer reactions that require different arrangements of these modules. Two of these methyl transfer reactions occur during turnover, when homocysteine is converted to methionine by using a methyl group derived from methyltetrahydrofolate. The third reaction is occasionally required for reactivation of the enzyme and uses S-adenosyl-L-methionine as the methyl donor. The absorbance properties of the cobalamin cofactor have been exploited to assign conformations of the protein and to probe the effect of ligands and mutations on the distribution of conformers. The results imply that the methylcobalamin form of MetH exists as an ensemble of interconverting conformational states. Differential binding of substrates or products alters the distribution of conformers. Furthermore, steric conflicts disfavor conformers that juxtapose a methyl group on substrate with one on methylcobalamin. These results suggest that the methylation state of the cobalamin will influence the distribution of conformers during turnover.

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Mapping the interactions between flavodoxin and its physiological partners flavodoxin reductase and cobalamin-dependent methionine synthase

Cited by 91 publications

References 33 publications

The IL1α-S100A13 Heterotetrameric Complex Structure

The IL1α-S100A13 Heterotetrameric Complex Structure

Solution Structures and Backbone Dynamics of a Flavodoxin MioC from Escherichia coli in both Apo- and Holo-forms

Factors modulating conformational equilibria in large modular proteins: A case study with cobalamin-dependent methionine synthase

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