Protein and amino acid composition of silks from the cob weaver, Latrodectus hesperus (black widow)

Casem, Merri Lynn; Turner, Dianna; Houchin, Kelly

doi:10.1016/s0141-8130(98)00078-6

Cited by 59 publications

(46 citation statements)

References 19 publications

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“…tubuliform glands were largely composed of alanine (26%) and serine (22%) ( Table 1). These compositions closely matched those reported for tubuliform glands (16) and egg case silk fibers (11,17) of other araneoid spiders. Moreover, the predicted amino acid compositions of the A.ar.…”

Section: Tusp1 Amino Acid Composition Matches Gland and Silk Compositsupporting

confidence: 86%

“…Recently, Hu et al (15) reported another putative component of egg case silk (ECP-1) expressed in silk glands of the black widow spider, Latrodectus hesperus. However, the translated sequence of neither ADF-2 nor ECP-1 could account for the amino acid composition of tubuliform silk fibers or the gland's contents (4,11,15,16,17), indicating that the dominant silk expressed by tubuliform glands must be a different, unidentified protein (4).…”

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confidence: 99%

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Modular evolution of egg case silk genes across orb-weaving spider superfamilies

Garb

Hayashi

2005

Proc. Natl. Acad. Sci. U.S.A.

110

132

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Spider silk proteins (fibroins) are renowned for their extraordinary mechanical properties and biomimetic potential. Despite extensive evolutionary, ecological, and industrial interest in these fibroins, only a fraction of the known silk types have been characterized at the molecular level. Here we report cDNA and genomic sequences of the fibroin TuSp1, which appears to be the major component of tubuliform gland silk, a fiber exclusively synthesized by female spiders for egg case construction. We obtained TuSp1 sequences from 12 spider species that represent the extremes of phylogenetic diversity within the Orbicularia (orb-weaver superfamilies, Araneoidea and Deinopoidea) and finer scale sampling within genera. TuSp1 encodes tandem arrays of an Ϸ200-aa-long repeat unit and individual repeats are readily aligned, even among species that diverged >125 million years ago. Analyses of these repeats across species reveal the strong influence of concerted evolution, resulting in intragenic homogenization. However, deinopoid TuSp1 repeats also contain insertions of coding, minisatellite-like sequences, an apparent result of replication slippage and nonreciprocal recombination. Phylogenetic analyses of 37 spider fibroin sequences support the monophyly of TuSp1 within the spider fibroin gene family, consistent with a single origin of this ortholog group. The diversity of taxa and silks examined here confirms that repetitive architecture is a general feature of this gene family. Moreover, we show that TuSp1 provides a clear example of modular evolution across a range of phylogenetic levels. concerted evolution ͉ fibroin ͉ gene family ͉ spider silk ͉ TuSp1

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Section: Tusp1 Amino Acid Composition Matches Gland and Silk Compositsupporting

confidence: 86%

mentioning

confidence: 99%

Modular evolution of egg case silk genes across orb-weaving spider superfamilies

Garb

Hayashi

2005

Proc. Natl. Acad. Sci. U.S.A.

110

132

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“…28 Protein and amino acid composition of silks from the black widow spider (Latrodectus hesperus) show variation between dragline, inner egg case, and scaffolding silks. 29 The inner silk of the egg case contains a higher proportion of Ala compared with Gly, possibly being high in crystalline -sheet content for strength to protect the eggs. Both the scaffolding silk (used for structural purposes) and dragline silk contain higher percentages of Gly over Ala, as is the case for Nephila clavipes dragline silk.…”

Section: Introductionmentioning

confidence: 99%

Orientational order of Australian spider silks as determined by solid‐state NMR

et al. 2006

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A simple solid-state NMR method was used to study the structure of 13 C-and 15 Nenriched silk from two Australian orb-web spider species, Nephila edulis and Argiope keyserlingi. Carbon-13 and 15 N spectra from alanine-or glycine-labeled oriented dragline silks were acquired with the fiber axis aligned parallel or perpendicular to the magnetic field. The fraction of oriented component was determined from each amino acid, alanine and glycine, using each nucleus independently, and attributed to the ordered crystalline domains in the silk. The relative fraction of ordered alanine was found to be higher than the fraction of ordered glycine, akin to the observation of alanine-rich domains in silk-worm (Bombyx mori) silk. A higher degree of crystallinity was observed in the dragline silk of N. edulis compared with A. keyserlingi, which correlates with the superior mechanical properties of the former #

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“…The major and minor ampullate fibroins contain the highest levels of glycine and alanine relative to other spider silk family members; these levels approach >50% of the total amino acid content (Casem et al, 1999;Lombardi & Kaplan, 1990). Biochemical experiments show dragline silk is a composite material largely composed of two structural proteins or spidroins (contraction of the words spider and fibroin) called MaSp1 and MaSp2 (Xu and Lewis, 1990;Hinman and Lewis, 1991).…”

Section: Molecular Components Of Dragline Silkmentioning

confidence: 99%