Proteome analysis of shell matrix proteins in the brachiopod Laqueus rubellus

Abstract

BackgroundThe calcitic brachipod shells contain proteins that play pivotal roles in shell formation and are important in understanding the evolution of biomineralization. Here, we performed a large-scale exploration of shell matrix proteins in the brachiopod Laqueus rubellus.ResultsA total of 40 proteins from the shell were identified. Apart from five proteins, i.e., ICP-1, MSP130, a cysteine protease, a superoxide dismutase, and actin, all other proteins identified had no homologues in public databases. Among these unknown proteins, one shell matrix protein was identified with a domain architecture that includes a NAD(P) binding domain, an ABC-type transport system, a transmembrane region, and an aspartic acid rich region, which has not been detected in other biominerals. We also identified pectin lyase-like, trypsin inhibitor, and saposin B functional domains in the amino acid sequences of the shell matrix proteins. The repertoire of brachiopod shell matrix proteins also contains two basic amino acid-rich proteins and proteins that have a variety of repeat sequences.ConclusionsOur study suggests an independent origin and unique mechanisms for brachiopod shell formation.Electronic supplementary materialThe online version of this article (doi:10.1186/s12953-015-0077-2) contains supplementary material, which is available to authorized users.

Evolutionary dynamics of origin and loss in the deep history of phospholipase D toxin genes

“…The Hydractinia sequence was identified from a study of transcriptomes in feeding, reproductive and defensive polyps, and was expressed specifically in feeding polyps [62]. The Laqueus sequence was reported in a proteomic and transcriptomic study of the brachiopod shell matrix, and was identified specifically from the insoluble organic matrix [63]. These observations suggest that members of the Aquatic clade may play diverse biological roles.…”

Insights into the Evolution of Shells and Love Darts of Land Snails Revealed from Their Matrix Proteins

“…We performed a shotgun approach to identify matrix proteins. The detailed procedures of tryptic peptide preparation and LC-MS/MS analysis are described in a previous study (Isowa et al. 2015).…”

“…We removed the low confidence PSMs and used the list of retained PSMs (FDR < 0.01) for the final protein identification. Parameters used for identification processes described earlier were the same as those in a previous study (Isowa et al. 2015).…”

Supplemental Material: Lithium isotope composition of modern and fossilized Cenozoic brachiopods

“…Proteomic studies suggest that, relative to other marine calcifiers, brachiopods precipitate their shells using a novel molecular mechanism. In the process, they might utilize an enzyme similar to that found in corals (αcarbonic anhydrase) to increase calcite precipitation rate (Jackson et al, 2015;Immel et al, 2015;Isowa et al, 2015). The secondary shell layer, most commonly used for reconstructions of paleoenvironmental conditions, is composed of calcite fibers that behave optically like single calcite crystals (Pérez-Huerta et al, 2018).…”