Nitrogenase: the reaction between iron protein and bathophenanthrolinedisulfonate as a probe for interactions with MgATP

Ljones, Torbjørn; Burris, R. H.

doi:10.1021/bi00603a010

Cited by 128 publications

(107 citation statements)

References 33 publications

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“…For example, the electron paramagnetic resonance (EPR) spectrum becomes more axial (45), and there Annual Reviews www.annualreviews.org/aronline is a 60-100-mV decrease in the redox potential when AXP 2 is bound to Fe-protein (46). A dramatic effect of nucleotide binding is evidenced the change in accessibility of the cluster to chelators (47)(48)(49). Specifically, the cluster irons can be removed by chelators only in the presence of MgATP; MgADP inhibits chelation, whereas no chelation occurs in the absence of nucleotide.…”

Section: Fe-proteinmentioning

confidence: 99%

Nitrogenase: A Nucleotide-Dependent Molecular Switch

Howard¹

1994

Annual Review of Biochemistry

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Section: Fe-proteinmentioning

confidence: 99%

Nitrogenase: A Nucleotide-Dependent Molecular Switch

Howard¹

1994

Annual Review of Biochemistry

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“…Unfortunately, the ET stopped-flow (SF) experiment cannot be used to count the number of electrons transferred, because the change in extinction coefficient upon oxidation of Fe red (ATP) 2 is not known with adequate accuracy, with values between 3,800 and 8,400 mM −1 ·cm −1 having been reported (23)(24)(25)(26)(27). As a result, we adopted an alternative counting strategy.…”

mentioning

confidence: 99%

Negative cooperativity in the nitrogenase Fe protein electron delivery cycle

Danyal

Shaw

Page

et al. 2016

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

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Nitrogenase catalyzes the ATP-dependent reduction of dinitrogen (N2) to two ammonia (NH3) molecules through the participation of its two protein components, the MoFe and Fe proteins. Electron transfer (ET) from the Fe protein to the catalytic MoFe protein involves a series of synchronized events requiring the transient association of one Fe protein with each αβ half of the α2β2 MoFe protein. This process is referred to as the Fe protein cycle and includes binding of two ATP to an Fe protein, association of an Fe protein with the MoFe protein, ET from the Fe protein to the MoFe protein, hydrolysis of the two ATP to two ADP and two Pi for each ET, Pi release, and dissociation of oxidized Fe protein-(ADP)2 from the MoFe protein. Because the MoFe protein tetramer has two separate αβ active units, it participates in two distinct Fe protein cycles. Quantitative kinetic measurements of ET, ATP hydrolysis, and Pi release during the presteady-state phase of electron delivery demonstrate that the two halves of the ternary complex between the MoFe protein and two reduced Fe protein-(ATP)2 do not undergo the Fe protein cycle independently. Instead, the data are globally fit with a two-branch negative-cooperativity kinetic model in which ET in one-half of the complex partially suppresses this process in the other. A possible mechanism for communication between the two halves of the nitrogenase complex is suggested by normal-mode calculations showing correlated and anticorrelated motions between the two halves.

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“…Apo-dinitrogenase reductase for this study was prepared by Priya Rangaraj as previously described (13,24). Briefly, 2.0 mg of purified dinitrogenase reductase was incubated with 20 mol of ␣, ␣Ј-dipyridyl in the presence of 2.5 mM MgATP and 2 mM sodium dithionite.…”

Section: Methodsmentioning

confidence: 99%

ADP-Ribosylation of Variants of Azotobacter vinelandii Dinitrogenase Reductase by Rhodospirillum rubrum Dinitrogenase Reductase ADP-Ribosyltransferase

et al. 2000

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In a number of nitrogen-fixing bacteria, nitrogenase is posttranslationally regulated by reversible ADPribosylation of dinitrogenase reductase. The structure of the dinitrogenase reductase from Azotobacter vinelandii is known. In this study, mutant forms of dinitrogenase reductase from A. vinelandii that are affected in various protein activities were tested for their ability to be ADP-ribosylated or to form a complex with dinitrogenase reductase ADP-ribosyltransferase (DRAT) from Rhodospirillum rubrum. R140Q dinitrogenase reductase could not be ADP-ribosylated by DRAT, although it still formed a cross-linkable complex with DRAT. Thus, the Arg 140 residue of dinitrogenase reductase plays a critical role in the ADP-ribosylation reaction. Conformational changes in dinitrogenase reductase induced by an F135Y substitution or by removal of the Fe 4 S 4 cluster resulted in dinitrogenase reductase not being a substrate for ADP-ribosylation. Through cross-linking studies it was also shown that these changes decreased the ability of dinitrogenase reductase to form a crosslinkable complex with DRAT. Substitution of D129E or deletion of Leu 127, which result in altered nucleotide binding regions of these dinitrogenase reductases, did not significantly change the interaction between dinitrogenase reductase and DRAT. Previous results showed that changing Lys 143 to Gln decreased the binding between dinitrogenase reductase and dinitrogenase (L. C. Seefeldt, Protein Sci. 3:2073-2081, 1994); however, this change did not have a substantial effect on the interaction between dinitrogenase reductase and DRAT.

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Nitrogenase: the reaction between iron protein and bathophenanthrolinedisulfonate as a probe for interactions with MgATP

Cited by 128 publications

References 33 publications

Nitrogenase: A Nucleotide-Dependent Molecular Switch

Nitrogenase: A Nucleotide-Dependent Molecular Switch

Negative cooperativity in the nitrogenase Fe protein electron delivery cycle

ADP-Ribosylation of Variants of Azotobacter vinelandii Dinitrogenase Reductase by Rhodospirillum rubrum Dinitrogenase Reductase ADP-Ribosyltransferase

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