scholarly journals Amino acid sequences of α-helical segments from S-carbosymethylkerateine-A. Complete sequence of a type-I segment

1978 ◽  
Vol 173 (2) ◽  
pp. 373-385 ◽  
Author(s):  
K H Gough ◽  
A S Inglis ◽  
W G Crewther
Keyword(s):  
Amino Acid ◽  
Sequence Data ◽  
Coiled Coil ◽  
Alpha Helix ◽  
Protein S ◽  
Amino Acid Sequences ◽  
Type I ◽  
Type Ii ◽  
Sequencing Data ◽  
Helical Segment

The amino acid sequence of a type-I helical segment from the low-sulphur protein (S-carboxymethylkerateine-A) of wool was determined by combining automatic and manual-sequencing data. Whereas in the type-II helical segment most of the cationic groups occur in pairs, 11 of the 22 anionic residues in the sequence of the type-I segment were situated next to a second anionic residue. This suggests possible interactions between type-I and type-II helical segments in alpha-keratin. As observed with the sequence of a type-II helical segment a model constructed on 3.6 residues per turn of helix shows a line of hydrophobic residues along the helix, thereby supporting the physicochemical evidence that the molecule is predominantly helical and forms part of a coiled-coil structure. Examination of the sequence data by predictive methods indicates the possibilty of extensive sections of alpha-helix interspersed with discontinuities. The molecule contains a number of regions with peptide sequences identical with those found by other workers after enzymic digestion of fractions from oxidized wool.

scholarly journals Amino acid sequences of α-helical segments from S-carboxymethylkerateine-A. Complete sequence of a type-II segment

1978 ◽  
Vol 173 (2) ◽  
pp. 365-371 ◽  
Author(s):  
W G Crewther ◽  
A S Inglis ◽  
N M McKern
Keyword(s):  
Amino Acid ◽  
Coiled Coil ◽  
Complete Sequence ◽  
Amino Acid Sequences ◽  
Helical Axis ◽  
Type I ◽  
Type Ii ◽  
Coil Structure ◽  
Aqueous Urea ◽  
Alpha Keratin

1. The helical fragments obtained by partial chymotryptic digestion of S-carboxymethylkeratine-A, the low-sulphur fraction from wool, were fractionated into type-I and type-II helical segments in aqueous urea under conditions limiting carbamoylation. 2. The amino acid sequence of a 109-residue type-II segment was completed by using the sequenator. 3. When the data were incorporated into a helical model of 3.6 residues per turn the hydrophobic residues generated a band aligned at a slight angle to the helical axis. This result is in accord with the postulated coiled-coil structure of the crystalline regions of alpha-keratin.

scholarly journals The amino acid sequence of component 7c, a type II intermediate-filament protein from wool

1989 ◽  
Vol 261 (3) ◽  
pp. 1015-1022 ◽  
Author(s):  
L G Sparrow ◽  
C P Robinson ◽  
D T W McMahon ◽  
M R Rubira
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Intermediate Filament ◽  
Coiled Coil ◽  
British Library ◽  
Intermediate Filament Protein ◽  
Type I ◽  
Type Ii ◽  
Blocking Group ◽  
Intermediate Filament Proteins

Component 7c is one of the four homologous type II intermediate-filament proteins that, by association with the complementary type I proteins, form the microfibrils or intermediate filaments in wool. Component 7c was isolated as the S-carboxymethyl derivative from Merino wool and its amino acid sequence was determined by manual and automatic sequencing of peptides produced by chemical and enzymic cleavage reactions. It is an N-terminally blocked molecule of 491 residues and Mr (not including the blocking group) of 55,600; the nature of the blocking group has not been determined. The predicted secondary structure shows that component 7c conforms to the now accepted pattern for intermediate-filament proteins in having a central rod-like region of approximately 310 residues of coiled-coil alpha-helix flanked by non-helical N-and C-terminal regions. The central region is divided by three non-coiled-coil linking segments into four helical segments 1A, 1B, 2A and 2B. The N-and C-terminal non-helical segments are 109 and 71 residues respectively and are rich in cysteine. Details of procedures use in determining the sequence of component 7c have been deposited as a Supplementary Publication SUP 50152 (65 pages) at the British Library Document Supply Centre, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1989) 257,5. The information comprises: (1) details of chemical and enzymic methods used for cleavage of component 7c, peptides CN1, CN2 and CN3, and various other peptides, (2) details of the procedures used for the fractionation and purification of peptides from (1), including Figures showing the elution profiles from the chromatographic steps used, (3) details of methods used to determine the C-terminal sequence of peptide CN3, and (4) detailed evidence to justify a number of corrections to the previously published sequence.

scholarly journals The primary structure of component 8c-1, a subunit protein of intermediate filaments in wool keratin. Relationships with proteins from other intermediate filaments

1986 ◽  
Vol 236 (3) ◽  
pp. 695-703 ◽  
Author(s):  
L M Dowling ◽  
W G Crewther ◽  
A S Inglis
Keyword(s):  
Amino Acid ◽  
Intermediate Filaments ◽  
Coiled Coil ◽  
Amino Acid Sequences ◽  
British Library ◽  
Type I ◽  
Intermediate Filament Proteins ◽  
Complete Sequences ◽  
Acetyl Group ◽  
Keratin Filament

Component 8c-1, one of four highly homologous component-8 subunit proteins present in the microfibrils of wool, was isolated as its S-carboxymethyl derivative and its amino acid sequence was determined. Large peptides were isolated after cleaving the protein chemically or enzymically and the sequence of each was determined with an automatic Sequenator. The peptides were ordered by sequence overlaps and, in some instances, by homology with known sequences from other component-8 subunits. The C-terminal residues were identified by three procedures. Full details of the various procedures used have been deposited as Supplementary Publication SUP 50133 (4 pp.) at the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1986) 233, 5. The result showed that the protein comprises 412 residues and has an Mr, including the N-terminal acetyl group, of 48,300. The sequence of residues 98-200 of component 8c-1 was found to correspond to the partial or complete sequences of four homologous type I helical segments previously isolated from helical fragments recovered from chymotryptic digests of microfibrillar proteins of wool [Crewther & Dowling (1971) Appl. Polym. Symp. 18, 1-20; Crewther, Gough, Inglis & McKern (1978) Text. Res. J. 48, 160-162; Gough, Inglis & Crewther (1978) Biochem. J. 173, 385]. Considered in relation to amino acid sequences of other intermediate-filament proteins, the sequence is in accord with the view that keratin filament proteins are of two types [Hanukoglu & Fuchs (1983) Cell (Cambridge, Mass.) 33, 915-924]. Filament proteins from non-keratinous tissues, such as desmin, vimentin, neurofilament proteins and the glial fibrillary acidic protein, which form monocomponent filaments, constitute a third type. It is suggested that as a whole the proteins from intermediate filaments be classed as filamentins, the three types at present identified forming subgroups of this class. The significant homologies between types I, II and III occur almost exclusively in segments of the chain that have been identified as having a coiled-coil structure together with the relatively short sections connecting these segments. The non-coiled-coil segments at the C- and N-termini show no significant homology between types, nor is homology in these segments apparent in all members of one type. Component 8c-1 does not show homology in its terminal segments with the known sequence of any other filamentin.(ABSTRACT TRUNCATED AT 400 WORDS)

Structure of α-keratin: Structural implication of the amino acid sequences of the type I and type II chain segments

1977 ◽  
Vol 113 (2) ◽  
pp. 449-454 ◽  
Author(s):  
D.A.D. Parry ◽  
W.G. Crewther ◽  
R.D.B. Fraser ◽  
T.P. MacRae
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequences ◽  
Type I ◽  
Type Ii

scholarly journals A comparison of the enzymological and biophysical properties of two distinct classes of dehydroquinase enzymes

1992 ◽  
Vol 282 (3) ◽  
pp. 687-695 ◽  
Author(s):  
C Kleanthous ◽  
R Deka ◽  
K Davis ◽  
S M Kelly ◽  
A Cooper ◽  
...  
Keyword(s):  
Catalytic Mechanism ◽  
Analytical Ultracentrifugation ◽  
Sedimentation Coefficient ◽  
Weighted Average ◽  
Alpha Helix ◽  
Amino Acid Sequences ◽  
Type I ◽  
Type Ii ◽  
Scanning Calorimetry ◽  
Typical Type

This paper compares the biophysical and mechanistic properties of a typical type I dehydroquinase (DHQase), from the biosynthetic shikimate pathway of Escherichia coli, and a typical type II DHQase, from the quinate pathway of Aspergillus nidulans. C.d. shows that the two proteins have different secondary-structure compositions; the type I enzyme contains approx. 50% alpha-helix while the type II enzyme contains approx. 75% alpha-helix. The stability of the two types of DHQase was compared by denaturant-induced unfolding, as monitored by c.d., and by differential scanning calorimetry. The type II enzyme unfolds at concentrations of denaturant 4-fold greater than the type I and through a series of discrete transitions, while the type I enzyme unfolds in a single transition. These differences in conformational stability were also evident from the calorimetric experiments which show that type I DHQase unfolds as a single co-operative dimer at 57 degrees C whereas the type II enzyme unfolds above 82 degrees C and through a series of transitions suggesting higher orders of structure than that seen for the type I enzyme. Sedimentation and Mr analysis of both proteins by analytical ultracentrifugation is consistent with the unfolding data. The type I DHQase exists predominantly as a dimer with Mr = 46,000 +/- 2000 (a weighted average affected by the presence of monomer) and has a sedimentation coefficient s0(20,w) = 4.12 (+/- 0.08) S whereas the type II enzyme is a dodecamer, weight-average Mr = 190,000 +/- 10,000 and has a sedimentation coefficient, s0(20,w) = 9.96 (+/- 0.21) S. Although both enzymes have reactive histidine residues in the active site and can be inactivated by diethyl pyrocarbonate, the possibility that these structurally dissimilar enzymes catalyse the same dehydration reaction by the same catalytic mechanism is deemed unlikely by three criteria: (1) they have very different pH/log kcat. profiles and pH optima; (2) imine intermediates, which are known to play a central role in the mechanism of type I enzymes, could not be detected (by borohydride reduction) in the type II enzyme; (3) unlike Schiff's base-forming type I enzymes, there are no conserved lysine residues in type II amino acid sequences.

scholarly journals Techniques for the verification of minimal phylogenetic trees illustrated with ten mammalian haemoglobin sequences

1980 ◽  
Vol 187 (1) ◽  
pp. 65-74 ◽  
Author(s):  
D Penny ◽  
M D Hendy ◽  
L R Foulds
Keyword(s):  
Amino Acid ◽  
Phylogenetic Tree ◽  
Protein Sequence ◽  
Phylogenetic Trees ◽  
Sequence Data ◽  
Protein Sequences ◽  
Nucleotide Sequences ◽  
Amino Acid Sequences ◽  
Minimal Tree ◽  
Protein Sequence Data

We have recently reported a method to identify the shortest possible phylogenetic tree for a set of protein sequences [Foulds Hendy & Penny (1979) J. Mol. Evol. 13. 127–150; Foulds, Penny & Hendy (1979) J. Mol. Evol. 13, 151–166]. The present paper discusses issues that arise during the construction of minimal phylogenetic trees from protein-sequence data. The conversion of the data from amino acid sequences into nucleotide sequences is shown to be advantageous. A new variation of a method for constructing a minimal tree is presented. Our previous methods have involved first constructing a tree and then either proving that it is minimal or transforming it into a minimal tree. The approach presented in the present paper progressively builds up a tree, taxon by taxon. We illustrate this approach by using it to construct a minimal tree for ten mammalian haemoglobin alpha-chain sequences. Finally we define a measure of the complexity of the data and illustrate a method to derive a directed phylogenetic tree from the minimal tree.

scholarly journals Molecular characterization of the coat protein gene revealed considerable diversity of viral species complex in Garlic (Allium sativum L.)

2020 ◽  
Author(s):  
Abel Debebe Mitiku ◽  
Dawit Tesfaye Degefu ◽  
Adane Abraham ◽  
Desta Mejan ◽  
Pauline Asami ◽  
...  
Keyword(s):  
Amino Acid ◽  
Coat Protein ◽  
Species Complex ◽  
Sequence Data ◽  
Amino Acid Sequences ◽  
Viral Gene ◽  
Planting Material ◽  
Virus C ◽  
Garlic Virus ◽  
Material Exchange

AbstractGarlic is one of the most crucial Allium vegetables used as seasoning of foods. It has a lot of benefits from the medicinal and nutritional point of view; however, its production is highly constrained by both biotic and abiotic challenges. Among these, viral infections are the most prevalent factors affecting crop productivity around the globe. This experiment was conducted on eleven selected garlic accessions and three improved varieties collected from different garlic growing agro-climatic regions of Ethiopia. This study aimed to identify and characterize the isolated garlic virus using the coat protein (CP) gene and further determine their phylogenetic relatedness. RNA was extracted from fresh young leaves, thirteen days old seedlings, which showed yellowing, mosaic, and stunting symptoms. Pairwise molecular diversity for CP nucleotide and amino acid sequences were calculated using MEGA5. Maximum Likelihood tree of CP nucleotide sequence data of Allexivirus and Potyvirus were conducted using PhyML, while a neighbor-joining tree was constructed for the amino acid sequence data using MEGA5. From the result, five garlic viruses were identified viz. Garlic virus C (78.6 %), Garlic virus D (64.3 %), Garlic virus X (78.6 %), Onion yellow dwarf virus (OYDV) (100%), and Leek yellow stripe virus (LYSV) (78.6 %). The study revealed the presence of complex mixtures of viruses with 42.9 % of the samples had co-infected with a species complex of Garlic virus C, Garlic virus D, Garlic virus X, OYDV, and LYSV. Pairwise comparisons of the isolated Potyviruses and Allexiviruses species revealed high identity with that of the known members of their respected species. As an exception, less within species identity was observed among Garlic virus C isolates as compared with that of the known members of the species. Finally, our results highlighted the need for stepping up a working framework to establish virus-free garlic planting material exchange in the country which could result in the reduction of viral gene flow across the country.Author SummaryGarlic viruses are the most devastating disease since garlic is the most vulnerable crop due to their vegetative nature of propagation. Currently, the garlic viruses are the aforementioned production constraint in Ethiopia. However, so far very little is known on the identification, diversity, and dissemination of garlic infecting viruses in the country. Here we explore the prevalence, genetic diversity, and the presence of mixed infection of garlic viruses in Ethiopia using next generation sequencing platform. Analysis of nucleotide and amino acid sequences of coat protein genes from infected samples revealed the association of three species from Allexivirus and two species from Potyvirus in a complex mixture. Ultimately the article concludes there is high time to set up a working framework to establish garlic free planting material exchange platform which could result in a reduction of viral gene flow across the country.

scholarly journals Seven new mutations in the nicotinamide adenine dinucleotide reduced–cytochrome b5 reductase gene leading to methemoglobinemia type I

Blood ◽  
2001 ◽  
Vol 97 (4) ◽  
pp. 1106-1114 ◽  
Author(s):  
Jan Dekker ◽  
Michel H. M. Eppink ◽  
Rob van Zwieten ◽  
Thea de Rijk ◽  
Angel F. Remacha ◽  
...  
Keyword(s):  
Amino Acid ◽  
Nicotinamide Adenine Dinucleotide ◽  
Cytochrome B5 ◽  
Enzyme Inactivation ◽  
Amino Acid Substitutions ◽  
Type I ◽  
Type Ii ◽  
3 Dimensional ◽  
Cytochrome B5 Reductase ◽  
Fad Binding

Abstract Cytochrome b5 reductase (b5R) deficiency manifests itself in 2 distinct ways. In methemoglobinemia type I, the patients only suffer from cyanosis, whereas in type II, the patients suffer in addition from severe mental retardation and neurologic impairment. Biochemical data indicate that this may be due to a difference in mutations, causing enzyme instability in type I and complete enzyme deficiency or enzyme inactivation in type II. We have investigated 7 families with methemoglobulinemia type I and found 7 novel mutations in the b5R gene. Six of these mutations predicted amino acid substitutions at sites not involved in reduced nicotinamide adenine dinucleotide (NADH) or flavin adenine dinucleotide (FAD) binding, as deduced from a 3-dimensional model of human b5R. This model was constructed from comparison with the known 3-dimensional structure of pig b5R. The seventh mutation was a splice site mutation leading to skipping of exon 5 in messenger RNA, present in heterozygous form in a patient together with a missense mutation on the other allele. Eight other amino acid substitutions, previously described to cause methemoglobinemia type I, were also situated in nonessential regions of the enzyme. In contrast, 2 other substitutions, known to cause the type II form of the disease, were found to directly affect the consensus FAD-binding site or indirectly influence NADH binding. Thus, these data support the idea that enzyme inactivation is a cause of the type II disease, whereas enzyme instability may lead to the type I form.

scholarly journals Structural studies on lamin. Similarities and differences between lamin and intermediate-filament proteins

1986 ◽  
Vol 238 (1) ◽  
pp. 305-308 ◽  
Author(s):  
D A D Parry ◽  
J F Conway ◽  
P M Steinert
Keyword(s):  
Amino Acid ◽  
Coiled Coil ◽  
Amino Acid Sequences ◽  
Ionic Interactions ◽  
Structural Studies ◽  
Intermediate Filament Proteins ◽  
Coiled Coil Domain ◽  
Similarities And Differences ◽  
Almost Continuous

Analysis of the amino acid sequences of lamins A and C has revealed that each chain has an almost continuous heptad-containing coiled-coil domain containing structural regularities in the linear disposition of the acidic and the basic residues. The data suggest that the lamin molecules are two-stranded ropes, that the two chains are parallel to one another and in axial register, and that the molecules aggregate in vivo through periodic ionic interactions. These results indicate that significant changes in stability of the nuclear envelope may be achieved between interphase and mitosis through changes in the degree of phosphorylation of the lamin proteins.

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