Subunit Orientation in the Filamentous VirusFf(fd, f1, M13)

Overman, Stacy A.; Tsuboi, Masamichi; Thomas, George J.

doi:10.1006/jmbi.1996.0323

Cited by 74 publications

(125 citation statements)

References 29 publications

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“…The intensity ratio I bb /I cc of the amide I band at 1649 cm À1 is 0.38, which is very close to the value of 0.36 predicted by Rintoul et al for a-helices running parallel to the hair shaft [21]. Our results for human hair compare well with experimental values of 0.39 and 0.33 for sheep's wool [21] and viruses [18], respectively. The intensity ratios I bc /I cc and I cb /I cc differ significantly from the expected value of zero, which may be attributed to factors such as disordering of the polypeptide strands, limitations of the model employed or experimental inaccuracies.…”

Section: Discussionsupporting

confidence: 91%

“…As a result of the fitting process, the ratio I bb / I cc of the amide I band at 1649 cm À1 is here determined to be 0.38. This is very close to the value of 0.36, predicted for a-helices running parallel to the hair shaft [21,27] [18]. According to the model expressed by Eq.…”

supporting

confidence: 75%

“…Polarized Raman measurements have the additional capacity of identifying the spatial orientation of macromolecular polymer films and fibers [14][15][16]. Corresponding studies on biopolymers span the range from comparably simple systems like polyalanine [17] up to large assemblies like viruses and bacteriophages [18][19][20]. Also studies on keratin-containing samples have been made; for example, Rintoul et al performed polarized Raman measurements on sheep's wool and feathers [21], and Pé zolet and coworkers investigated silk threads from silkworms and spiders [22,23].…”

mentioning

confidence: 96%

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Polarized Raman microspectroscopy on intact human hair

Ackermann

Koster

Schlücker

2008

Journal of Biophotonics

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Polarization-resolved Raman microspectroscopy with near-infrared laser excitation was applied to intact human hair in order to non-invasively investigate the conformation and orientation of the polypeptide chains. By varying the orientation of the hair shaft relative to the polarization directions of the laser/analyzer, a set of four polarized Raman spectra is obtained; this allows to simultaneously determine both the secondary structure of hair proteins and the orientation of the polypeptide strands relative to the axis of the hair shaft. For the amide I band, results from a quantitative analysis of the polarized Raman spectra are compared with theoretically expected values for fibers with uniaxial symmetry. Based on the polarization behavior of the amide I band and further vibrational bands, a partial ordering of alpha-helical polypeptide strands parallel to the hair shaft can be concluded. We suggest that this microspectroscopic approach may be used for human hair diagnostics by detecting structural or orientational alterations of keratins.

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Section: Discussionsupporting

confidence: 91%

supporting

confidence: 75%

mentioning

confidence: 96%

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Polarized Raman microspectroscopy on intact human hair

Ackermann

Koster

Schlücker

2008

Journal of Biophotonics

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“…Taken together, the proposed contacts between two coat proteins can be summarized in a model, in which the two proteins are tilted. There are indications that such a tilted conformation of coat protein occurs in a lipid bilayer, and it has been shown that the protein is tilted about 20 o with respect to the membrane normal (26). When two interacting coat proteins are tilted against each other at an angle of 40 o , residues 23, 27, 31, and 35 are in close contact (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Remarkably, in the phage particle, the coat proteins are also tilted at an angle of about 20 o compared to the phage axis (22,26). However, in the phage the coat proteins form an interdigitated helical array, such that one protein comes into contact with 10 neighboring subunits.…”

Section: Discussionmentioning

confidence: 99%

Cysteine Residues in the Transmembrane Regions of M13 Procoat Protein Suggest that Oligomeric Coat Proteins Assemble onto Phage Progeny

Nagler

Kühn

2007

J Bacteriol

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The M13 phage assembles in the inner membrane of Escherichia coli. During maturation, about 2,700 copies of the major coat protein move from the membrane onto a single-stranded phage DNA molecule that extrudes out of the cell. The major coat protein is synthesized as a precursor, termed procoat protein, and inserts into the membrane via a Sec-independent pathway. It is processed by a leader peptidase from its leader (signal) peptide before it is assembled onto the phage DNA. The transmembrane regions of the procoat protein play an important role in all these processes. Using cysteine mutants with mutations in the transmembrane regions of the procoat and coat proteins, we investigated which of the residues are involved in multimer formation, interaction with the leader peptidase, and formation of M13 progeny particles. We found that most single cysteine residues do not interfere with the membrane insertion, processing, and assembly of the phage. Treatment of the cells with copper phenanthroline showed that the cysteine residues were readily engaged in dimer and multimer formation. This suggests that the coat proteins assemble into multimers before they proceed onto the nascent phage particles. In addition, we found that when a cysteine is located in the leader peptide at the ؊6 position, processing of the mutant procoat protein and of other exported proteins is affected. This inhibition of the leader peptidase results in death of the cell and shows that there are distinct amino acid residues in the M13 procoat protein involved at specific steps of the phage assembly process.

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