An Interpretive Basis of the Proton Nuclear Magnetic Resonance Hyperfine Shifts for Structure Determination of High-Spin Ferric Hemoproteins. Implications for the Reversible Thermal Unfolding of Ferricytochrome<i>c</i>‘ from<i>Rhodopseudomonas palustris</i>

Clark, Kimber; Dugad, L. B.; Bartsch, Robert G.; Cusanovich, and Michael A.; Mar, Gerd N. La

doi:10.1021/ja953719t

Cited by 29 publications

(61 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2, where it can be seen that unique resonances, most of which have intensities corresponding to one or three protons, are observed that are similar in general appearance to those of previously studied high-spin Fe(III) proteins (36), especially horseradish peroxidase (36,44,45) and cytochrome cЈ (36,(46)(47)(48). The assigned heme methyl and propionate resonances of NP2 (34) and its distal pocket mutants are labeled.…”

Section: Proton Nmr Spectra Of the High-spin (S ‫؍‬ 5͞2) (No-free) Fomentioning

confidence: 63%

Electrochemical and NMR spectroscopic studies of distal pocket mutants of nitrophorin 2: Stability, structure, and dynamics of axial ligand complexes

Shokhireva

Berry

Uno

et al. 2003

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

152

View full text Add to dashboard Cite

Section: Proton Nmr Spectra Of the High-spin (S ‫؍‬ 5͞2) (No-free) Fomentioning

confidence: 63%

Electrochemical and NMR spectroscopic studies of distal pocket mutants of nitrophorin 2: Stability, structure, and dynamics of axial ligand complexes

Shokhireva

Berry

Uno

et al. 2003

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

152

View full text Add to dashboard Cite

“…The CO 2 Ϫ H-bond strength requires definitive assignments and quantitation of the hyperfine shifts in hHO-DMDH/PH-H 2 O, which because it is high spin and exhibits, by a factor of ϳ20, stronger paramagnetic relaxation than the low spin cyanide complex (48) is more of a challenge but likely attainable (53,54). Such studies are in progress.…”

Section: Molecular Topology Of Apohho In Solution-mentioning

confidence: 99%

1H NMR Investigation of the Solution Structure of Substrate-free Human Heme Oxygenase

Syvitski

Auclair

et al. 2004

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

1 H NMR was used to investigate the molecular structure, and dynamic properties of soluble, recombinant, substrate-free human heme oxygenase (apohHO) on a comparative basis with similar studies on the substrate complex. Limited but crucial sequence-specific assignments identify five conserved secondary structural elements, and the detection of highly characteristic dipolar or H-bond interactions among these elements together with insignificant chemical shift differences confirm a strongly conserved folding topology of helices C-H relative to that of substrate complexes in either solution or the crystal. The correction of the chemical shifts for paramagnetic and porphyrin ring current influences in the paramagnetic substrate complex reveals that the strength of all but one of the numerous relatively robust H-bonds are conserved in apohHO, and similar ordered water molecules are located near these H-bond donors as observed in the substrate complexes. The unique and significant weakening of the Tyr 58 OH hydrogen bond to the catalytically critical Asp 140 carboxylate in apohHO is suggested to arise from the removal of the axial Hbond acceptor ligand rather than the loss of substrate. The interhelical positions of the conserved strong Hbonds argue for a structural role in maintaining a conserved structure for helices C-H upon loss of substrate. While the structure and H-bond network are largely conserved upon loss of substrate, the variably increased rate of NH lability dictates a significant loss of dynamic stability in the conserved structure, particularly near the distal helix F. Heme oxygenase (HO)1 is a non-metal enzyme that catalyzes the regiospecific cleavage of heme to yield ␣-biliverdin, iron, and CO (1). Heme serves as both cofactor and substrate in a reaction that consumes three O 2 molecules, seven electrons, and nine protons (2-5). HOs are found in mammals as ϳ32-kDa membrane-bound enzymes in the key roles of heme metabolism, iron conservation (HO1) (6, 7) and generator of a putative neural messenger (HO2) (8). Smaller, soluble analogs have been identified in pathogenic bacteria that are used to mine iron from the host (9, 10) and in plants and photosynthetic bacteria where they generate light-harvesting pigments (11). The mechanism of HO appears the same despite the diverse origins of the enzymes and involves the iron-hydroperoxy, rather than the common ferryl heme, as the species that attacks the ␣-meso position (2, 4, 12). Recent crystal structures of substrate-bound complexes of first a recombinant, soluble construct of mammalian HO (13, 14) (human HO (hHO)) and then rat HO (rHO) (15-17) followed by two bacterial HOs (18, 19) have revealed novel all-␣-helical enzymes comprised of eight helices (A-H) with the heme wedged between helix A, which provides the highly conserved proximal His, and a conserved distal helix F that exhibits a significant kink near a Gly-Gly or Gly-Ala linkage. The ␣-stereoselectivity of the HO reaction has been attributed to a combination of obvious steric blockage of all but ...

show abstract

“…Although sharing just 19% sequence identity and 40% similarity (23), Cyt cЈ and Cyt b 562 have quite similar folds (1.6-Å rms deviation in ␣-carbon position) ( Fig. 1) (27)(28)(29)(30)(31)(32). In Cyt cЈ, the side-chain of Leu-12 fills the space occupied by a sixth ligand in Cyt b 562 (Fig.…”

mentioning

confidence: 99%

Cytochrome c ′ folding triggered by electron transfer: Fast and slow formation of four-helix bundles

Lee

Gray

Winkler

2001

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

View full text Add to dashboard Cite

E nergy-landscape descriptions of protein folding emphasize the roles of free energy and energy-surface ruggedness as key determinants of folding dynamics (1-3). The many correlations of folding times with free energy support this point of view, but it is difficult to reconcile the model with the seemingly simple kinetics that often are observed. Analyses of experimental data point to a relationship between the folding kinetics and the topology of the native protein structure (4-8). Proteins that, on average, have a large number of long-range contacts in the folded state tend to fold more slowly than those with a preponderance of short-range contacts. The questions remain: is it the depth and roughness of the funnel, the topology of the folded state, or some combination of the two that determines the folding mechanism? Short-range contacts outnumber long-range interactions in helical bundles; if topology is the key, then these proteins should fold rapidly (4, 5). Highly helical ferrocytochrome b 562 (Fe II -Cyt b 562 ) (9, 10), acyl-CoA binding protein (ACBP) (11)(12)(13)(14), the E colicin binding immunity proteins Im7 and Im9 (15,16), and the N-terminal domain of phage repressor (17) all fold on the millisecond time scale. These observations appear to support the notion that folded-state structural topology is of central importance in folding dynamics and that helical bundle structures are inherently fast folding.

show abstract

An Interpretive Basis of the Proton Nuclear Magnetic Resonance Hyperfine Shifts for Structure Determination of High-Spin Ferric Hemoproteins. Implications for the Reversible Thermal Unfolding of Ferricytochromec‘ fromRhodopseudomonas palustris

Cited by 29 publications

References 47 publications

Electrochemical and NMR spectroscopic studies of distal pocket mutants of nitrophorin 2: Stability, structure, and dynamics of axial ligand complexes

Electrochemical and NMR spectroscopic studies of distal pocket mutants of nitrophorin 2: Stability, structure, and dynamics of axial ligand complexes

1H NMR Investigation of the Solution Structure of Substrate-free Human Heme Oxygenase

Cytochrome c ′ folding triggered by electron transfer: Fast and slow formation of four-helix bundles

Contact Info

Product

Resources

About