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

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.

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Type II intermediate-filament proteins from wool. The amino acid sequence of component 5 and comparison with component 7c

Biochemical Journal ◽

10.1042/bj2820291 ◽

1992 ◽

Vol 282 (1) ◽

pp. 291-297 ◽

Cited By ~ 13

Author(s):

L G Sparrow ◽

C P Robinson ◽

J Caine ◽

D T W McMahon ◽

P M Strike

Keyword(s):

Amino Acid ◽

Amino Acid Sequence ◽

Intermediate Filament ◽

Sequence Similarity ◽

British Library ◽

Intermediate Filament Protein ◽

Type Ii ◽

Blocking Group ◽

Intermediate Filament Proteins ◽

Merino Wool

Component 5 is one of the four type II intermediate-filament proteins found in the hard keratin wool. It 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. Component 5 is an N-terminally blocked molecule of 503 residues and Mr (not including the blocking group) of 56,600. The blocking group has not been identified. The amino acid sequence of component 5 shows 77% sequence identity with that of component 7c, another type II wool intermediate-filament protein [Sparrow, Robinson, McMahon & Rubira (1989) Biochem. J. 261, 1015-1022]. The sequence similarity extends from the N-termini of the two molecules to residue 459 (component 5 sequence); however, there is no recognizable sequence similarity in the remaining C-terminal 43 amino acid residues. Details of procedures used in determining the sequence of component 5 have been deposited as a Supplementary Publication SUP 50168 (80 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. (1992) 281, 5. The information comprises: (1) details of chemical and enzymic methods used for cleavage of component 5, peptide CN1, the peptide mixture CN2/3 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, and (3) details of the method used to determine the C-terminal sequence of component 5.

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

Biochemical Journal ◽

10.1042/bj2360695 ◽

1986 ◽

Vol 236 (3) ◽

pp. 695-703 ◽

Cited By ~ 60

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)

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Secondary structure of component 8c-1 of α-keratin. An analysis of the amino acid sequence

Biochemical Journal ◽

10.1042/bj2360705 ◽

1986 ◽

Vol 236 (3) ◽

pp. 705-712 ◽

Cited By ~ 65

Author(s):

L M Dowling ◽

W G Crewther ◽

D A Parry

Keyword(s):

Amino Acid ◽

Secondary Structure ◽

Amino Acid Sequence ◽

Intermediate Filament ◽

Coiled Coil ◽

Terminal Region ◽

Striking Similarity ◽

Intermediate Filament Proteins ◽

Coil Structure ◽

Alpha Keratin

The amino acid sequence of component 8c-1 from alpha-keratin was analysed by using secondary-structure prediction techniques, homology search methods, fast Fourier-transform techniques to detect regularities in the linear disposition of amino acids, interaction counts to assess possible modes of chain aggregation and assessment of hydrophilicity distribution. The analyses show the following. The molecule has two lengths of coiled-coil structure, each about 20 nm long, one from residues 56-202 with a discontinuity from about residue 91 to residue 101, and the other from residues 219-366 with discontinuities from about residue 238 to residue 245 and at about residue 306. The acidic and basic residues in the coiled-coil segment between residues 102 and 202 show a 9,4-residue structural period in their linear disposition, whereas between residues 246 and 366 a period of 9.9 residues is observed in the positioning of ionic residues. Acidic and basic residues are out of phase by 180 degrees. Similar repeats occur in corresponding regions of other intermediate-filament proteins. The overall mean values for the repeats are 9.55 residues in the N-terminal region and 9.85 residues in the C-terminal region. The regions at each end of the protein chain (residues 1-55 and 367-412) are not alpha-helical and contain many potential beta-bends. The regions specified in have a significant degree of homology mainly due to a semi-regular disposition of proline and half-cystine residues on a three-residue grid; this is especially apparent in the C-terminal segment, in which short (Pro-Cys-Xaa)n regions occur. The coiled-coil segments of component 8c-1 bear a striking similarity to corresponding segments of other intermediate-filament proteins as regards sequence homology, structural periodicity of ionic residues and secondary/tertiary-structure predictions. The assessments of the probabilities that these homologies occurred by chance indicate that there are two populations of keratin filament proteins. The non-coiled-coil regions at each end of the chain are less hydrophilic than the coiled-coil regions. Ionic interactions between the heptad regions of components 8c-1 and 7c from the microfibrils of alpha-keratin are optimized when a coiled-coil structure is formed with the heptad regions of the constituent chains both parallel and in register.

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Genes for intermediate filament proteins and the draft sequence of the human genome

Journal of Cell Science ◽

10.1242/jcs.114.14.2569 ◽

2001 ◽

Vol 114 (14) ◽

pp. 2569-2575 ◽

Cited By ~ 1

Author(s):

Michael Hesse ◽

Thomas M. Magin ◽

Klaus Weber

Keyword(s):

Human Genome ◽

Dna Sequences ◽

Intermediate Filament ◽

Muscle Protein ◽

Gene Families ◽

Type I ◽

Type Ii ◽

Draft Sequence ◽

Intermediate Filament Proteins ◽

Processed Pseudogenes

We screened the draft sequence of the human genome for genes that encode intermediate filament (IF) proteins in general, and keratins in particular. The draft covers nearly all previously established IF genes including the recent cDNA and gene additions, such as pancreatic keratin 23, synemin and the novel muscle protein syncoilin. In the draft, seven novel type II keratins were identified, presumably expressed in the hair follicle/epidermal appendages. In summary, 65 IF genes were detected, placing IF among the 100 largest gene families in humans. All functional keratin genes map to the two known keratin clusters on chromosomes 12 (type II plus keratin 18) and 17 (type I), whereas other IF genes are not clustered. Of the 208 keratin-related DNA sequences, only 49 reflect true keratin genes, whereas the majority describe inactive gene fragments and processed pseudogenes. Surprisingly, nearly 90% of these inactive genes relate specifically to the genes of keratins 8 and 18. Other keratin genes, as well as those that encode non-keratin IF proteins, lack either gene fragments/pseudogenes or have only a few derivatives. As parasitic derivatives of mature mRNAs, the processed pseudogenes of keratins 8 and 18 have invaded most chromosomes, often at several positions. We describe the limits of our analysis and discuss the striking unevenness of pseudogene derivation in the IF multigene family. Finally, we propose to extend the nomenclature of Moll and colleagues to any novel keratin.

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Developmentally regulated cytokeratin gene in Xenopus laevis.

Molecular and Cellular Biology ◽

10.1128/mcb.5.10.2575 ◽

1985 ◽

Vol 5 (10) ◽

pp. 2575-2581 ◽

Cited By ~ 37

Author(s):

J A Winkles ◽

T D Sargent ◽

D A Parry ◽

E Jonas ◽

I B Dawid

Keyword(s):

Amino Acid ◽

Xenopus Laevis ◽

Intermediate Filament ◽

Type I ◽

Developmentally Regulated ◽

Amino Acid Homology ◽

Intermediate Filament Proteins ◽

Functional Roles ◽

Terminal Domain ◽

Terminal Domains

We have determined the sequence of cloned cDNAs derived from a 1,665-nucleotide mRNA which transiently accumulates during Xenopus laevis embryogenesis. Computer analysis of the deduced amino acid sequence revealed that this mRNA encodes a 47-kilodalton type I intermediate filament subunit, i.e., a cytokeratin. As is common to all intermediate filament subunits so far examined, the predicted polypeptide, named XK70, contains N- and C-terminal domains flanking a central alpha-helical rod domain. The overall amino acid homology between XK70 and a human 50-kilodalton type I keratin is 47%; homology within the alpha-helical domain is 57%. The N-terminal domain, which is not completely contained in our cDNAs, is basic, contains 42% serine plus alanine, and includes five copies of a six-amino-acid repeating unit. The C-terminal domain has a high alpha-helical content and contains a region with sequence homology to the C-terminal domains of other type I and type III intermediate filament proteins. We suggest that different keratin filament subtypes may have different functional roles during amphibian oogenesis and embryogenesis.

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The predicted amino acid sequence of alpha-internexin is that of a novel neuronal intermediate filament protein.

The EMBO Journal ◽

10.1002/j.1460-2075.1990.tb08169.x ◽

1990 ◽

Vol 9 (3) ◽

pp. 749-755 ◽

Cited By ~ 92

Author(s):

K.H. Fliegner ◽

G.Y. Ching ◽

R.K. Liem

Keyword(s):

Amino Acid ◽

Amino Acid Sequence ◽

Intermediate Filament ◽

Predicted Amino Acid Sequence ◽

Intermediate Filament Protein ◽

Filament Protein

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

Biochemical Journal ◽

10.1042/bj1730365 ◽

1978 ◽

Vol 173 (2) ◽

pp. 365-371 ◽

Cited By ~ 41

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.

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