Carboxypeptidase Y from Saccharomyces cerevisiae: circular dichroism and fluorescence studies.

Carboxypeptidase Y was isolated from Saccharomyces cerevisiae and its molecular structure investigated. The enzyme in the native state possesses 40% of its amino acid residues in a beta-conformation. Its tryptophan residues seem to be largely buried in an apolar and unsymmetrical environment.     

Conformational analysis of proteins from circular dichroism spectra with reference to human erythrocuprein

Zusammenfassung Nachweis mittels vergleichender CD-Spektraluntersuchungen bei einer Auflösung von 2.5 nm von Erythrocuprein, Myoglobin, Lysozym und Ribonuklease, dass menschliches Erythrocuprein keinen oder nur einen geringen Teil mit -helicoidaler Struktur hat.     

A simple device for measurement of circular dichroism in the visible and ultraviolet regions

Zusammenfassung Es wird ein einfacher Apparat beschrieben, der als Zusatzgerät zum. Zeiss-Spektralphotometer PMQ II zur Messung von Zirkulardichroismus zu verwenden ist.     

Effect of volatile anesthetics on the circular dichroism of bilirubin bound to human serum albumin

The characteristic circular dichroism of bilirubin bound to human serum albumin undergoes a remarkable sign inversion on addition of halothane, chloroform and other volatile anesthetics. This sign inversion, which is completely reversed by removal of the anesthetic, reflects a pronounced conformational change of the bound ligand; probably a complete inversion of chirality. The observation suggests that association of volatile anesthetics with proteins can markedly alter the internal topography of receptor sites and potentially influence the stereoselectivity of ligand binding.     

Studies on the behaviour of circular dichroism of different haemoglobins in the 260 nm region

Zusammenfassung CD-Messungen mit hoher Auflösung an Hämoglobinen verschiedener Spezies ergaben eine Aufspaltung der breiten Absorptionsbande bei 260 nm in 4 einzelne Maxima. Diese stimmen mit der Bandenlage des Phenylalanins im Absorptionsspektrum vom Hämoglobin gut Überein und werden daher diesem Chromophor zugeordnet.     

Effect of volatile anesthetics on the circular dichroism of bilirubin bound to human serum albumin.

The characteristic circular dichroism of bilirubin bound to human serum albumin undergoes a remarkable sign inversion on addition of halothane, chloroform and other volatile anesthetics. This sign inversion, which is completely reversed by removal of the anesthetic, reflects a pronounced conformational change of the bound ligand; probably a complete inversion of chirality. The observation suggests that association of volatile anesthetics with proteins can markedly alter the internal topography of receptor sites and potentially influence the stereoselectivity of ligand binding.     

Determination of the binding constant of thiamine diphosphate in transketolase from baker's yeast by circular dichroism titration

Zusammenfassung Mit Hilfe des Circulardichroismus wurde die Bindungskonstante von Thiamindiphosphat in der Transketolase der Bäckerhefe bestimmt.     

The problem of calculating the circular dichroism signals of the 10 nearest neighbor configurations of DNA]

Due to linear constraints over the nearest neighbour frequencies the order of the linear dependence of DNA CD spectra is 8. The computation of the CD signals of the 10 nearest neighbour configurations is therefore not possible if these signals are linearly independent. We show that the method proposed by Allen et coll. does not allow to obtain these signals.     

Circular dichroism of acetoacetylated proteins

Riassunto Sono state analizzate le variazioni conformazionali indotte nella ribonucleasi pancreatica di bue (RNase A) e nel lisozima del bianco di uovo dopo acetoacetilazione con differenti quantità di dichetene. La modifica dell'attività enzimatica, susseguente al trattamento con dichetene, non è attribuibile a variazioni conformazionali delle proteine considerate ma al bloccaggio selettivo di uno o piÚ gruppi amminici coinvolti nell'attività catalitica o nel binding≒ col substrato.     

Interaction between an antifungal heptaene, amphotericin B and cholesterol in vitro, as detected by circular dichroism and absorption. Influence of temperature]

The polyene antibiotic "Amphotericin B" can interact with sterols, cholesterol or ergosterol in aqueous and hydroalcoholic media and a correlative striking spectral change appears between 300 and 420 nm in the CD and absorption spectra. Using these spectroscopic methods we have determined that the influence of temperature between 4 and 80 degrees C is very important. The higher the temperature the most rapid is the modification of the spectra. Thus, the "Amphotericin B"-sterol complex is more easily formed when heating. We have not found any reversibility at 80 degrees C.     

Paracelsin; characterization by NMR spectroscopy and circular dichroism,and hemolytic properties of a peptaibol antibiotic from the cellulolytically active mnoldTrichoderma reesei. Part B

Summary Paracelsin, a hemolytic and membrane active polypeptide antibiotic of the peptaibol class which is excreted by the moldTrichderma reesei, was obtained by a simplified and isolation procedure utilziing hydrophobic adsorber resin. Investigation by¹³C nuclear magnetic resonance spectroscopy and circular dichroism revealed considerable helical portions in solution, and the very recently accomplished sequence determination of paracelsin allows the discussion of the results with regard to the closely related analogues, alamethicin and suzukacillin. A selective cleavage of the peptide was achieved by careful treatment with various acids, and a buffer of pH 8.25 and of high ionic strength made possible the quantitative determination of the C-terminal phenylalaninol released by means of ion-exchange chromatography. The significance of the production of paracelsin and related mycotoxins of the peptaibol class, exhibiting various kinds of biological activity, is discussed with respect to the extensive effort being made towards biotechnological applications of species, strains and cellulolytically highly active mutants of the fungusTrichoderma.Presented in part at the 5th European Symposium on Animal, Plant and Microbial Toxins, Hannover, August 29–September 2, 1983 and a lecture given at Ciby-Geigy/Basel in March 1984.Acknowledgment. We thank I. Ackermann for excellent and skilled technical assistance and gratefully acknowledge the help of R. Ratz for support in CD spectroscopy.     

Carboxypeptidase Y fromSaccharomyces cerevisiae: Circular dichroism and fluorescence studies

Summary Carboxypeptidase Y was isolated fromSaccharomyces cerevisiae and its molecular structure investigated. The enzyme in the native state possesses 40% of its amino acid residues in a -conformation. Its tryptophan residues seem to be largely buried in an apolar and unsymmetrical environment.Acknowledgments. The authors are grateful to Professors Kanarek and Strosberg for the use of the Cary 61 spectropolarimeter and the Durum amino acid analyzer. This work was supported by a Grant of the Fonds National Belge de la Recherche Fondamentale et Collective and by a Grant of the Fonds Emile Defay. E.P. is Aspirant de Recherches of the Fonds National Belge de la Recherche Scientifique.