Protein-level evidence of novel β-type hemocyanin and heterogeneous subunit usage in the Pacific whiteleg shrimp, Litopenaeus vannamei

ABSTRACT: The functional diversity of crustacean hemocyanins is broad, encompassing O2 delivery, innate immune response, metabolite storage, and osmolyte balance, all in a heterogeneous protein structure. As such, the sequence diversity of this class of proteins and its subunit composition are the focus of many studies on crustacean adaptation to environmental challenges. Recent transcriptomic and genomic sequencing on the Pacific whiteleg shrimp Litopenaeus vannamei has identified unique isoforms of hemocyanin including an ancestral β-type subunit thought to be lost in penaeid shrimp. However, it is unknown the degree to which these isoforms are translated as proteins, and whether they differ in function. The present study uses proteomic approaches to characterize the protein-level abundance and organization of these hemocyanin isoforms within their native oligomeric structures. Fractions of each hemocyanin oligomeric form were purified by size-exclusion high performance liquid chromatography for identification of subunit isoforms using tandem mass spectrometry at <1% protein false discovery rate. Relative abundances of hemocyanin oligomers and monomeric subunits from hemolymph and fractions were also quantified by polyacrylamide gel electrophoresis with and without denaturation for comparison of relative abundance. Ten hemocyanin isoforms were identified by tandem mass spectrometry in both hemocyanin oligomer fractions including a single small subunit, eight large subunits, and the first protein-level evidence of a β-type subunit in penaeid shrimp. Hemocyanin subunits were organized primarily as hexamers (95-99% relative abundance) as opposed to dodecamers. Hexamers utilized a significantly higher ratio (2.05:1) of small subunit to large subunit compared to dodecamers (1.04:1), and the relative abundances of the large subunit isoforms was dominated by HcL1 in both fractions. The ability to distinguish and quantify hemocyanin isoforms within oligomeric structures will aid future studies linking hemocyanin genes to function and physiology as well as offer insight into the evolutionary history of crustaceans.

OTHER RELATED OMICS DATASETS IN: MODEL1109130000 MODEL1311110000 MODEL1909260003 MODEL1311110001 MODEL1909260004 MODEL1703310000 MODEL1909260005 MODEL1909260006

INSTRUMENT(S): TripleTOF 5600

ORGANISM(S): Penaeus Vannamei

TISSUE(S): Hemolymph

SUBMITTER: Jason Wang  

LAB HEAD: Karen Gray Burnett

PROVIDER: PXD014575 | Pride | 2020-02-07

REPOSITORIES: Pride