Correlation between Hydrogen Bond Lengths and Reduction Potentials in Clostridium pasteurianum Rubredoxin

Lin, I-Jin; Gebel, Erika; Machonkin, Timothy E.; Westler, William M.; Markley, John L.

doi:10.1021/ja028710n

Cited by 29 publications

(46 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These hydrogen bonds are purported to serve a dual purpose: they tune the cofactor E m as well as define ET pathways [65][66][67]. Markley and coworkers reported a 15 N NMR study of mutants of Val44 in Clostridium pasteurianum rubredoxin in which the hydrogen bond from the backbone amide at position 44 to the iron-ligating Cys42 varies systematically [68,69]. In these variants, no significant changes are noticed in the lengths of other hydrogen bonds.…”

Section: Rubredoxinsmentioning

confidence: 99%

Biological Outer-Sphere Coordination

Lancaster

2011

Molecular Electronic Structures of Transition Metal Complexes I

View full text Add to dashboard Cite

The concept of outer-sphere coordination (OSC) is surveyed in the context of bioinorganic chemistry. A distinction is made between electronic and structural OSC, both arising from the interaction of the protein matrix with inner sphere ligands. Electronic OSC entails the electronic interaction between the polypeptide and inner-sphere ligands. These effects principally arise from hydrogenbonding interactions, though through-space dipolar interactions are also encountered. Structural OSC comprises primarily steric effects that do not necessarily impact ligand electronics but rather influence inner sphere topology. Additionally, the protein matrix can be envisioned as a local "solvent" whose bulk dielectric and point charges influence the metal center. Recurring themes are highlighted where OSC regulates the properties of various metalloproteins distinguished by cofactors and/or function. Finally, cases are presented where OSC has guided molecular design.

show abstract

Section: Rubredoxinsmentioning

confidence: 99%

Biological Outer-Sphere Coordination

Lancaster

2011

Molecular Electronic Structures of Transition Metal Complexes I

View full text Add to dashboard Cite

show abstract

“…Investigations of thermally induced unfolding of CpRd showed that loss of the metal ion immediately precedes formation of the (apparently) unstructured apoRd [19], but that Fe(SCys) 4 site stability does not control the thermostability of the native folded structure [20]. Engineered V ↔ A exchanges of residue 44, which forms an N-H…S hydrogen bond to one of the ironcoordinating Cys residues, significantly raised and lowered the respective stabilities of the Fe(SCys) 4 sites in CpRd and PfRd [21][22][23][24] but had only minor effects on the thermal stabilities of the folded holoRds. Thiophilic metal ions (Cd II , Zn II ) can directly and isomorphically displace iron from the native Fe II (SCys) 4 site of CpRd under nondenaturing conditions and without unzipping of the β-sheet [25].…”

Section: Introductionmentioning

confidence: 99%

“Iron priming” guides folding of denatured aporubredoxins

Bonomi¹,

Iametti²,

Ferranti³

et al. 2008

J Biol Inorg Chem

View full text Add to dashboard Cite

The relationship between iron uptake by aporubredoxins (apoRds) and formation of native holorubredoxins (holoRd), including their Fe(SCys) 4 sites, was studied. In the absence of denaturants, apoRds exhibited spectroscopic features consistent with structures very similar to those of the folded holoRds. However, additions of either ferric or ferrous salts to the apoRds in the absence of denaturants gave less than 40% recovery of the native holoRd circular dichroism and UV-vis spectroscopic features. In the presence of either 6 M urea or 6 M guanidine hydrochloride, the nativelike structural features of the apoRds were absent. Nevertheless, nearly quantitative recoveries of the native holoRd spectroscopic features were achieved by addition of either ferric or ferrous salts to the denatured apoRds without diluting the denaturant. Consistent with this observation, the native spectroscopic features were unaffected by addition of the same denaturant concentrations to the as-isolated holoRds. Denaturing concentrations of urea or guanidine hydrochloride also increased the rates of holoRd recoveries from apoRds and ferrous salts. Mass spectrometry confirmed that ferric iron binding to the denatured apoRds precedes the recoveries of protein secondary structures and Fe(SCys) 4 sites. Thus, iron binding to the apoRds guides, both kinetically and thermodynamically, refolding to the native holoRd structures. Our results imply that the ferrous oxidation state would more efficiently drive formation of the native holoRd structure from the nascent apoprotein in vivo, but that the Fe(SCys) 4 site must attain the ferric state in order to achieve its native structure.Correspondence to: Francesco Bonomi. Electronic supplementary material The online version of this article

show abstract

“…The 15 N chemical shifts can resolve changes in H-bond distances on the order of 0.01 Å (19). Recently, an NMR study of a set of CpRd mutants revealed that electron delocalization onto the nitrogen of residue 44 varied with side-chain substitutions at this residue in a way that tracked changes in the reduction potential of the protein (21). This result has prompted us to carry out a comprehensive analysis of all six Fe-S⅐⅐⅐⅐⅐H N H-bonds of CpRd in a series of 10 sequence variants in their oxidized (Fe III ) and reduced (Fe II ) states.…”

mentioning

confidence: 99%

Changes in hydrogen-bond strengths explain reduction potentials in 10 rubredoxin variants

Lin¹,

Gebel²,

Machonkin³

et al. 2005

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

Self Cite

113

View full text Add to dashboard Cite

The rubredoxin from Clostridium pasteurianum (CpRd) provides an excellent system for investigating how the protein sequence modulates the reduction potential of the active site in an iron-sulfur protein. 15 N NMR spectroscopy has allowed us to determine with unprecedented accuracy the strengths of all six key hydrogen bonds between protein backbone amides and the sulfur atoms of the four cysteine residues that ligate the iron in the oxidized (Fe III ) and reduced (Fe II ) forms of wild-type CpRd and nine mutants (V44G, V44A, V44I, V44L, V8G, V8A, V8I, V8L, and V8G͞V44G). The length (or strength) of each hydrogen bond was inferred from the magnitude of electron spin delocalized across the hydrogen bond from the iron atom onto the nitrogen. The aggregate lengths of these six hydrogen bonds are shorter in both oxidation states in variants with higher reduction potential than in those with lower reduction potential. Differences in aggregate hydrogen bonding upon reduction correlate linearly with the published reduction potentials for the 10 CpRd variants, which span 126 mV. Sequence effects on the reduction potential can be explained fully by their influence on hydrogen-bond strengths.iron-sulfur protein ͉ reduction potential tuning ͉ 15 N NMR ͉ paramagnetic NMR

show abstract

Correlation between Hydrogen Bond Lengths and Reduction Potentials in Clostridium pasteurianum Rubredoxin

Cited by 29 publications

References 19 publications

Biological Outer-Sphere Coordination

Biological Outer-Sphere Coordination

“Iron priming” guides folding of denatured aporubredoxins

Changes in hydrogen-bond strengths explain reduction potentials in 10 rubredoxin variants

Contact Info

Product

Resources

About