The amino acid sequence of a single polypeptide chain, B-4, from fowl feather barbs has been determined. The B-4 chain was found to consist of 96 amino acid residues and to have a molecular weight of 10206 in the S-carboxymethylated form. The N terminus of this protein was an N-acetylserine residue. The B-4 protein contained seven S-carboxymethylcysteine residues, six of which are located in the N-terminal region (residues 1 -26), and other one in C terminus. The central region of the peptide chain was rich in hydrophobic residues. There were homologous amino acids at 66 positions in the sequences of the feather keratins of fowl, emu and silver gull. The variation (substitution, deletion and insertion) in sequence was found to be localized in both terminal sections of the polypeptide chain.The B-4 protein structure was predicted to contain fi-sheet (about 30 %), turn and random-coil-like structure, and no a-helix. P-Sheet structure is mostly located in the central region (residues 22-70). On the other hand, both terminal regions are almost devoid of secondary structure.Feather proteins are solubilized in the presence of denaturant by cleavage of disulfide cross-linkages of cystine residues with oxidant or reductant [l -31. Although soluble feather keratins from various birds have been reported to be relatively homogeneous with respect to molecular weight (about 10000) [4,S], they are at the same time heterogeneous by electrophoresis and chromatography and contain slightly different components [6,7]. It was found that an extract of emu feather gave the simplest electrophoretic pattern and that from silver gull was the next simplest. Thus single polypeptide chains were isolated from feather of these two avian species [8]. The present authors have reported on isolation and characteristics of soluble proteins from fowl feather barbs and calamus [9-111. From these studies it has been found that the components of each feather keratin are almost identical in amino acid composition except for cystine and/or amide content. O'Donnell [12] and O'Donnell and Inglis [13] determined amino acid sequences of the proteins from emu and silver gull feather calami, respectively. It was found that a central section, about 60-residues long, of the polypeptide chain contained predominantly hydrophobic residues and was free of S-carboxymethylcysteine, while both terminal sections were rich in S-carboxymethylcysteine. Fraser et al. estimated from infrared spectra data that about 30 % of the polypeptide chain in seagull feather rachis had an antiparallel pleated sheet conformation [14].The ultimate purposes of the present study were to elucidate (a) the whole structure of feather keratin and (b) the relation between the feather keratin sequence and the evolutionary developments in Aves. In this paper, the amino acid sequence of the main component of fowl feather barbs is reported. The sequence is compared with those of emu and silver gull feather calami.Abbreviations. Dansyl, 1-dimethylaminonaphthalene-5-sulphonyl; HPLC, high-performan...

The amide I Raman tensor corresponding to the antiparallel b-sheet structure in proteins has been determined by polarized Raman microspectroscopy of fowl feather rachis using polarized Raman spectra excited in the near-infrared (785 nm). For a Raman tensor principal axis system (XYZ), in which X is perpendicular to the plane of the pleated b-sheet, Y is in the plane of the sheet and perpendicular to the direction of the polypeptide chain, and Z is parallel to the direction of the polypeptide chain, the principal tensor components (a XX , a YY , a ZZ ) are found to satisfy the following relationships: R 1 ≡ a XX /a ZZ = 0.32 and R 2 ≡ a YY /a ZZ = 3.48. With this Raman tensor determination, we show that semiquantitative estimates of the total antiparallel b-sheet content in b-rich proteins can be extracted from polarized Raman intensity measurements on the amide I marker of the b-sheet occurring near 1664 cm −1 . We demonstrate this approach for the b-rich silk proteins of the silkworm and spider. INTRODUCTIONThe antiparallel chain, pleated-sheet conformation (ˇ-sheet) is a fundamental structural component of native proteins. 1 The silk of both silkworms and spiders and the rachis keratins of fowl feather barbs are examples of native proteins in which the antiparallelˇ-sheet is the major structural element. 2 A key property of theˇ-sheet structure in both silk and feathers is a high degree of polypeptide chain orientation. Thě -sheet conformation is also prevalent in nonnative and misfolded proteins and has been implicated in polypeptide † Presented as part of a commemorative issue for Wolfgang Kiefer on the occasion of his 65th birthday.

Fluoride has been used to prevent caries in the dentition, but the possible underlying mechanisms of cytotoxicity induction by this compound are still unclear. Since fluoride is known as an inhibitor of glycolytic enzymes, we investigated the possible connection between NaF-induced apoptosis and glycolysis in human promyelocytic leukemia HL-60 cells. NaF-induced apoptotic cell death is characterized by caspase activation, internucleosomal DNA fragmentation, loss of mitochondrial membrane potential, and production of apoptotic bodies. Higher activation of caspases-3 and -9, as compared with that of caspase-8, suggested the involvement of an extrinsic pathway. Utilization of glucose was nearly halted by NaF, whereas that of glutamine was rather enhanced. NaF enhanced the expression of Bad protein, but not that of Bcl-2 and Bax proteins, and reduced HIF-1alpha mRNA expression. Analysis of these data suggests a possible link between glycolysis and apoptosis.

A fowl feather barb 10 pm in thickness was subjected to a polarized infrared spectroscopic measurement by the use of a microscopic device. Nearly 50% of its peptide groups were found to give the 1633 and 1684 cm-' bands characteristic of the antiparallel-chain pleated sheet structure, and the remaining 50% gave the 1659 cm-' band assignable to unordered polypeptide chains. The orientation of the pleated sheet was determined to be on average 9 = 52" and x = 39", where 9 and x are the angles for the transformation of the XYZ coordinate system fixed on the pleated sheet and the abc coordinate system fixed on the sample barb. The Raman spectra of the barb were also examined with another microscopic device and a 488.0-nm laser beam. A sharp aa component of the Raman scattering tensor was observed at 1667 cm-'. Based on this fact, a revised set of parameters for the vibrational couplings among the peptide groups in the pleated sheet has been proposed.Some discussions have been made on the amide I Raman tensor of the antiparallel-chain pleated sheet. On a aussi examine le spectre Raman de la barbette B l'aide d'un autre appareil microscopique et d'un faisceau de laser de 488,O nm. On a observC une forte composante aa du tenseur de diffusion Raman B 1667 cm-'. Sur la base de ce resultat, on propose un ensemble rCvist des paramktres de couplages vibrationnels parmi les groupes peptidiques du feuillet plisst.On prCsente aussi quelques discussions du tenseur Raman de I'amide I du feuillet plissC avec des chaines antiparallkles.