A structural model of the chitin-binding domain of cuticle proteins

Hamodrakas, Stavros J.; Willis, Judith H.; Iconomidou, Vassiliki A.

doi:10.1016/s0965-1748(02)00079-6

Cited by 86 publications

(76 citation statements)

References 32 publications

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“…The engineered juxtaposition of reactive groups such as quinone and histidine is known to promote cross-linking reactions (34). In insect cuticular proteins, a consensus sequence ("R&R consensus") involved with chitin binding (11,36,37) has been identified: in addition to the ideal location of His residues in the R&R consensus for subsequent cross-linking reactions, the consensus is predicted to form ␤-pleated sheets (36). Provided that His-rich domains in the beak proteins are also arranged according to a ␤-sheet conformation, they might play a role of stiff elements with a highly packed configuration, in which His residues are strategically presented by one or both faces of a series of sheets to be joined by reaction with the catecholic crosslinkers, as schematically illustrated in Fig.…”

Section: Discussionmentioning

confidence: 99%

Cross-linking Chemistry of Squid Beak

Miserez

Rubin

Waite

2010

Journal of Biological Chemistry

104

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In stark contrast to most aggressive predators, Dosidicus gigas (jumbo squids) do not use minerals in their powerful mouthparts known as beaks. Their beaks instead consist of a highly sclerotized chitinous composite with incremental hydration from the tip to the base. We previously reported L-3,4-dihydroxyphenylalanine (dopa)-histidine (dopa-His) as an important covalent cross-link providing mechanical strengthening to the beak material. Here, we present a more complete characterization of the sclerotization chemistry and describe additional cross-links from D. gigas beak. All cross-links presented in this report share common building blocks, a family of di-, tri-, and tetra-histidine-catecholic adducts, that were separated by affinity chromatography and high performance liquid chromatography (HPLC) and identified by tandem mass spectroscopy and proton nuclear magnetic resonance ( 1 H NMR). The data provide additional insights into the unusually high cross-link density found in mature beaks. Furthermore, we propose both a low molecular weight catechol, and peptidyl-dopa, to be sclerotization agents of squid beak. This appears to represent a new strategy for forming hard tissue in animals. The interplay between covalent cross-linking and dehydration on the graded properties of the beaks is discussed.Cephalopods such as squids, cuttlefish, and octopods are equipped with a hard beak that is as sharp as a knife and crucial for disabling prey and feeding. Beak chemistry has attracted much recent attention in materials science: in contrast to mammalian hard tissues, the beak is devoid of minerals, consisting instead of a composite of proteins and chitin fibers with varying degrees of hydration along the beak structure. In animals, this is a unique material design for hard tissues that function in biting. The Dosidicus beak biocomposite possesses a stiffness (elastic modulus, E) of 5 GPa at the distal tip that decreases incrementally to 50 MPa (wet conditions) in the proximal wing, which is tightly embedded within the muscular buccal mass (1). As the beak lacks any of the known strengthening entities previously associated with wear-resistant tissues such as biomineralization (2-5), metal ion cross-linking (6, 7), or protein halogenation (8, 9), it begs a question, namely, what sort of molecular processing can impart such impressive physical properties? A deeper understanding of the mechanisms by which beaks are sclerotized is also likely to reveal novel chemical paradigms for the fabrication of robust and biocompatible composites for a variety of restorative applications. Furthermore, synthesis of such polymer-based composite materials could inspire environmentally friendly routes as Dosidicus beak is formed under ambient seawater conditions and is wholly nontoxic.From a biochemical perspective the biomaterial most similar to Dosidicus beak is hard insect cuticle. Both are predominantly composed of chitin fibers, protein, and polyphenolic compounds (10, 11). In insect cuticle, the contribution of dehydration and cross-...

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Section: Discussionmentioning

confidence: 99%

Cross-linking Chemistry of Squid Beak

Miserez

Rubin

Waite

2010

Journal of Biological Chemistry

104

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“…Previous studies of insect cuticle proteins have suggested that the barrel structure formed by multiple ␤-strands provides an interface for aromatic residues to stack with and bind to chitin (27,28). In this regard, we note that several of the highly conserved residues in the Tweedle proteins that lie within these predicted ␤-strands have aromatic side chains: Y and H in block I, Y and F in block II, Y in block III and Y, and F and Y in block IV.…”

Section: Role Of Tweedle Proteins In Cuticle Assemblymentioning

confidence: 99%

Mutation of TweedleD, a member of an unconventional cuticle protein family, alters body shape in Drosophila

Guan

Middlebrooks

Alexander

et al. 2006

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

124

155

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Body shape determination represents a critical aspect of morphogenesis. In the course of investigating body shape regulation in Drosophila, we have identified a dominant mutation, TweedleD 1 (TwdlD 1 ), that alters overall dimensions at the larval and pupal stages. Characterization of the affected locus led to the discovery of a gene family that has 27 members in Drosophila and is found only among insects. Analysis of gene expression at the RNA and protein levels revealed gene-specific temporal and spatial patterns in ectodermally derived tissues. In addition, light microscopic studies of fluorescently tagged proteins demonstrated that Tweedle proteins are incorporated into larval cuticular structures. This demonstration that a mutation in a Drosophila cuticular protein gene alters overall morphology confirms a role for the fly exoskeleton in determining body shape. Furthermore, parallels between these findings and studies of cuticle collagen genes in Caenorhabditis elegans suggest that the exoskeleton influences body shape in diverse organisms.arthropod ͉ morphogenesis ͉ tandem duplication ͉ Tubby

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“…Predictions that the R&R Consensus serves to bind to chitin have been supported in various ways. The secondary structure of the R&R Consensus was proposed and experimentally analyzed; homology models for the tertiary structure exist (Iconomidou et al, 1999;Iconomidou et al, 2001;Hamodrakas et al, 2002;Iconomidou et al, 2005). Biochemical analyses using recombinant fusion proteins with the R&R Consensus confirmed that it can function as a chitinbinding domain (Rebers and Willis, 2001;Togawa et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Developmental expression patterns of cuticular protein genes with the R&R Consensus from Anopheles gambiae

Togawa

Dunn

Emmons

et al. 2008

Insect Biochemistry and Molecular Biology

Self Cite

106

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CPR proteins are the largest cuticular protein family in arthropods. The whole genome sequence of Anopheles gambiae revealed 156 genes that code for proteins with the R&R Consensus and named CPRs. This protein family can be divided into RR-1 and RR-2 subgroups, postulated to contribute to different regions of the cuticle. We determined the temporal expression patterns of these genes throughout post-embryonic development by means of real-time qRT-PCR. Based on expression profiles, these genes were grouped into 21 clusters. Most of the genes were expressed with sharp peaks at single or multiple periods associated with molting. Genes coding for RR-1 and RR-2 proteins were found together in several co-expression clusters. Twenty-five genes were expressed exclusively at one metamorphic stage. Five out of six X-linked genes showed equal expression in males and females, supporting the presence of a gene dosage compensation system in An. gambiae. Many RR-2 genes are organized into sequence clusters whose members are extremely similar to each other and generally closely associated on a chromosome. Most genes in each sequence cluster are expressed with the same temporal expression pattern and at the same level, suggesting a shared mechanism to regulate their expression.

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A structural model of the chitin-binding domain of cuticle proteins

Cited by 86 publications

References 32 publications

Cross-linking Chemistry of Squid Beak

Cross-linking Chemistry of Squid Beak

Mutation of TweedleD, a member of an unconventional cuticle protein family, alters body shape in Drosophila

Developmental expression patterns of cuticular protein genes with the R&R Consensus from Anopheles gambiae

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