摘要:

The total semi‐empirical conformational analysis of the oxytocin molecule has been carried out. It has been revealed the two main types of stable structures of cyclic moiety backbone and the great lability of the tail. The optimal spacing of cyclic moiety side chains has been found for every backbone structure. The calculation results are in good agreement with the data of physico‐chemical investigations. Among the set of stable molecule structures reported in the present study are structures with β‐turn conformation of the cyclic moiety backbone and without closer spacing of the cyclic moiety and the tail, as well as structures with closely spaced N‐ and C‐terminal parts which, however, lack β‐turn in the

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1979.tb01894.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Observations of extended peptide chains, whose direction is perpendicular to the fiber axis (cross‐β‐structures) have hitherto been confined to fibrous proteins and to some synthetic polydisperse polypeptides of rather low molecular weight. This structure has now been found in some monodisperse linear homooligopeptides with aliphatic hydrocarbon side chains. X‐ray diffraction photographs of t‐Boc‐(d‐Ala)7‐OMe and HCl·H(d‐Ala)7‐OMe show characteristic reflections for this form. In addition, the good orientation of suitably prepared specimens has enabled a fairly complete determination of the unit cell of the heptapeptides to be made. t‐Boc‐(d‐Ala)7‐OMe and HCl·H(d‐Ala)7‐OMe molecules are packed in a monoclinic lattice with a = 4.80, b = 34.5, c = 5.82 Å, β = 65.6° and a = 4.80, b = 29.5, c = 5.82 Å, β = 65.6°, respectively. It has not been possible to establish whether the arrangement of the chains within

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1979.tb01895.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

The α‐amino group of bovine Growth Hormone was selectively modified with TNBS with no detectable changes in growth promoting activity. TNP was used as hapten for the production of antibodies against the end terminal region of bGH. The region near the α‐amino group is not involved in the binding of bGH to rat liver cells, and it seems to be away from the part of the molecule that interacts with the cell binding

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1979.tb01896.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

We have predicted the secondary structures of four beta‐lactamases /Bacillus cereus, Bacillus licheniformis, Staphylococcus aureus, and Escherichia coli R‐TEM) by the statistical method of Chou&Fasman as well as by the information theory method of Garnier et al. The secondary structures of all four beta‐lactamases are of the alpha/beta type (Levitt&Chothias's nomenclature), with helices at N‐ and C‐termini. There are about eight short regions each of alpha‐helical (30–50%) and beta‐strand (10–20%) structure separated by about 20 reverse turns. The conformation of the Gram‐positive and Gram‐negative beta‐lactamases are generally similar although a few differences are predicted between the S.aureus and E.coli structures. Surprisingly, the two bacilli structures differ significantly in three short regions. In all four enzymes the region near the catalytically‐implicated tyrosine has similar secondary structure. The secondary structure of hen egg white lysozyme, a penicillin‐binding enzyme, as well as T4 phage lysozyme, has similarities to the N‐terminal half of the penicill

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1979.tb01897.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

The α and β subunits of human follitropin were isolated in a high state of purity. The tryptophan fluorescence of the native hormone and the isolated β subunit are different. The N‐terminus of the α and β subunits was identified as valine and aspartic acid respectively. While recombination of the isolated α and β subunits restores the electrophoretic mobility of the intact hormone, its receptor binding activity cannot be fully regenerated. Substitution of the human follitropin α by an ovine lutropin α subunit, to form a recombinant with the follitropin β subunit, generates a complex with 2–3 receptor binding activity of the native human follitropin and the same activity as ovine follitropin. Acylation of the intact hormone does not disrupt the quaternary structure but leads to complete inactivation. Acylation studies with the subunits suggests the crucial role of the ∍‐amino groups of the α subunit in determining b

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1979.tb01898.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

The series of diastereomeric peptide derivatives N‐benzoyl‐d,l‐X‐N‐benzyl‐oxycarbonyl‐L‐lysine methyl ester where X = alanyl, valyl, leucyl, phenylalanyl and isoleucyl are submitted as model systems for studying racemization in peptide synthesis. The diastereomers can be analyzed by quantitation of the separated ester methyl proton peaks of their nuclear magnetic resonance spectra. Data on the tendency to racemize of the different residues are presented. In polar solvents, valyl and isoleucyl residues racemize more readily than the

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1979.tb01899.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

The soluble proteins from bovine lens homogenate were separated on Sepharose CL‐6B (2 times 200 cm) in 0.05mtris‐NaHSO3pH 8.2 buffer containing 20 mM EDTA. Five sharp and defined fractions (HMα, α, βH, βL, γ) were obtained. Each crystallin fraction was further purified by rechromatography on the same column. Each protein fraction was pure as judged by ultracentrifugation and SDS‐gel electrophoresis. The molecular weights of the five fractions were 3.04 times 106, 5.83 times 105, 1.58 times 105, 4.59 times 104, 2.14 times 104as determined from sedimentation coefficient and intrinsic viscosity data by Scheraga‐Mandelkern equation, which was in close agreement with that obtained by gel filtration. The polypeptide composition of crystallins as determined by SDS‐gel electrophoresis revealed one band for high molecular weight α (HMα) and α, three for βH, two for βL and one for γ.The gross CD patterns of crystallins were about the same in the peptide region (200 nm ˜ 250 nm) with a minimum centered at about 217 nm, indicative of α β‐sheet structure in all crystallins. The [0] values at 217 nm ranged from –1700 to –3700 degrees cm2per decimole. The CD spectra of these crystallins in the aromatic region (250 nm ˜ 300 nm) were different, reflecting the different contributions of aromatic amino acids to the ter

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1979.tb01900.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

A study was conducted to determine the effect of amino acid sequence and aspartyl protecting group on the rate of base catalyzed succinimide formation in the solid‐phase synthesis of aspartyl peptides. The peptides H‐Ala‐Asp‐Gly‐Phe‐OH and H‐Ala‐Asp‐Leu‐Phe‐OH were synthesized by the solid‐phase method with cyclopentyl or benzyl protection for the β‐carboxyl of aspartic acid. The results showed that the cyclopentyl ester was notably less susceptible to succinimide formation by treatment with tertiary amine than was the benzyl ester, and that the difference could have significant consequences for the synthesis of large peptides which contain reactive

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1979.tb01901.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

[Glu(OMe)4] oxytocin (XVI) and [Mpr1, Glu(OMe)4] oxytocin (XVII) bearing a methyl ester group in place of the carboxamide group in position 4 of oxytocin were synthesized by (3 + 6) segment condensation using the S‐trityl group for the protection of the cysteine side chains. Analogue XVI exhibited 10.5 U/mg in vitro uterotonic, and 42 U/mg avian vasodepressor, activity, and analogue XVII 21.4 U/mg and 82 U/mg of the respective activities. Both compounds showed no response in the rat pressor assa

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1979.tb01902.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1979.tb01903.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY