A Nuclear Magnetic Resonance Study of the Metal Binding Sites in Bacitracin

1975 ◽  
Vol 53 (12) ◽  
pp. 1250-1254 ◽  
Author(s):  
Roderick E. Wasylishen ◽  
Moira R. Graham
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Metal Binding ◽  
Binding Sites ◽  
Imidazole Ring ◽  
Nuclear Magnetic Resonance Study ◽  
Resonance Spectroscopy ◽  
Metal Binding Sites ◽  
Ph Values ◽  
Nuclear Magnetic

Carbon-13 nuclear magnetic resonance spectroscopy has been used to identify sites in bacitracin which bind Cu2+ and Mn2+. Results are presented which implicate the free carboxyl groups of the aspartic and glutamic acid residues and the imidazole ring of the histidine residue as metal complexation sites between pH 6 and 8. Evidence is presented which also indicates that the thiazoline ring of bacitracin binds Mn2+. Bacitracin does not bind Cu2+ or Mn2+ at pH values of 2.5 or less.

Complexes of W(VI) and Mo(VI) with glycolic, lactic, chloro- and phenyl-lactic, mandelic, and glyceric acids studied by 1H and 13C nuclear magnetic resonance spectroscopy

1987 ◽  
Vol 65 (4) ◽  
pp. 827-832 ◽  
Author(s):  
M. Madalena Caldeira ◽  
M. Luisa Ramos ◽  
Victor M. S. Gil
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Sodium Tungstate ◽  
Sodium Molybdate ◽  
Nuclear Magnetic Resonance Study ◽  
Resonance Spectroscopy ◽  
Magnetic Resonance Study ◽  
Ph Values ◽  
13C Nuclear Magnetic Resonance ◽  
Nuclear Magnetic

A proton and carbon-13 nuclear magnetic resonance study is reported on the number, stoichiometry, geometry, and stability of the complexes that form when sodium tungstate or sodium molybdate is mixed with each one of the following α-hydroxyacids in aqueous solution at pH values in the range 3–8: glycolic, lactic, chloro-3- andphenyl-3-lactic, mandelic, and glyceric acids. The predominant complexes have 1:2 composition and pK of formation of the order of −5 to −16.

Peptide Conformations. I. Nuclear Magnetic Resonance Study of the Carbamate Reaction of Amino Acids and Peptides

1971 ◽  
Vol 49 (5) ◽  
pp. 767-776 ◽  
Author(s):  
R. U. Lemieux ◽  
M. A. Barton
Keyword(s):  
Amino Acids ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Nuclear Magnetic Resonance Study ◽  
Amide Bond ◽  
Resonance Spectroscopy ◽  
Peptide Conformations ◽  
End Distance ◽  
Phenylalanine Residue ◽  
Nuclear Magnetic

Nuclear magnetic resonance spectroscopy has been applied to the study of carbamate formation in solutions of amino acids and peptides in a carbonate-bicarbonate system. The possible conformations of these carbamates are discussed in terms of the n.m.r. data obtained. The n.m.r. parameters are reported for the diastereomers L-alanyl-L or D-phenylalanine and L-phenylalanyl-L or D-alanine and for the dipeptide glycyl-L-phenylalanine and their carbamates. The results are interpreted in terms of preferred rotamers about the Cα—Cβ bond of the phenylalanine residue and a β-type conformation of the peptide chain, wherein the two α-protons lie in the plane of the amide bond. All observations are in agreement with a shorter end to end distance in L,D- compared with L,L-dipeptides.

A 13C comparative nuclear magnetic resonance study of organic solute production and excretion by the yeasts Hansenula anomala and Saccharomyces cerevisiae in saline media

1988 ◽  
Vol 34 (5) ◽  
pp. 605-612 ◽  
Author(s):  
Yves Bellinger ◽  
François Larher
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Specific Property ◽  
Glucose Consumption ◽  
Nuclear Magnetic Resonance Study ◽  
Resonance Spectroscopy ◽  
Hansenula Anomala ◽  
Organic Solute ◽  
Nuclear Magnetic

Glycerol, arabitol and trehalose were the principle solutes detected in cellular extracts of Hansenula anomala, using natural-abundance 13C nuclear magnetic resonance spectroscopy. Only the two polyols accumulated in response to increased salinity, glycerol increase being far greater. Arabitol content also increased with culture age, independently of the presence or absence of salt and in line with the evolution of trehalose content. Glycerol retention potential was 15 times greater for Hansenula than for Saccharomyces cerevisiae. The former displayed the specific property of increasing this capacity in high salt concentrations. Under such conditions its growth was associated with a limited increase in glucose consumption per unit biomass, relative to S. cerevisiae, the salt-sensitive reference yeast. In addition, a polysaccharide, the chemical nature of which was not further characterized, was detected exclusively in the external medium of Hansenula growing in the presence of salt.

A 13C nuclear magnetic resonance study of selectivity in the binding of univalent counterions by heparin

1988 ◽  
Vol 66 (10) ◽  
pp. 2601-2604 ◽  
Author(s):  
Photis Dais ◽  
Kevin R. Holme ◽  
Arthur S. Perlin
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Nuclear Magnetic Resonance Study ◽  
Resonance Spectroscopy ◽  
Free Energies ◽  
Binding Selectivity ◽  
Hydrated Ions ◽  
Binding Preference ◽  
13C Nuclear Magnetic Resonance ◽  
Nuclear Magnetic

The binding selectivities of univalent counterions for heparin in the systems Ca2+/M+/HEP, where M+ = Li+, Na+, K+, Cs+, TMA+, have been studied by 13C nuclear magnetic resonance spectroscopy. Chemical shift displacements of the various 13C nuclei of heparin in these systems clearly indicate that the binding selectivity of the polymer for univalent counterions increases with an increase in the radius of the hydrated cation form, namely Li+ > Na+ > K+ > Cs+ > TMA+. An explanation for this binding preference is offered on the basis of electrostatic and entropic terms, whereby the latter is reflected in changes in the hydration volumes of the univalent cations. Differences in the magnitude of these hydration volumes, in relation to the free energies of hydration, may account for a binding selectivity that favours the more highly hydrated ions.

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