Splice variants of perlucin from Haliotis laevigata modulate the crystallisation of CaCO3.
Perlucin is one of the proteins of the organic matrix of nacre (mother of pearl) playing an important role in biomineralisation. This nacreous layer can be predominately found in the mollusc lineages and is most intensively studied as a compound of the shell of the marine Australian abalone Haliotis laevigata. A more detailed analysis of Perlucin will elucidate some of the still unknown processes in the complex interplay of the organic/inorganic compounds involved in the formation of nacre as a very interesting composite material not only from a life science-based point of view. Within this study we discovered three unknown Perlucin splice variants of the Australian abalone H. laevigata. The amplified cDNAs vary from 562 to 815 base pairs and the resulting translation products differ predominantly in the absence or presence of a varying number of a 10 mer peptide C-terminal repeat. The splice variants could further be confirmed by matrix-assisted laser desorption ionisation time of flight mass spectrometry (MALDI-ToF MS) analysis as endogenous Perlucin, purified from decalcified abalone shell. Interestingly, we observed that the different variants expressed as maltose-binding protein (MBP) fusion proteins in E. coli showed strong differences in their influence on precipitating CaCO3 and that these differences might be due to a splice variant-specific formation of large protein aggregates influenced by the number of the 10 mer peptide repeats. Our results are evidence for a more complex situation with respect to Perlucin functional regulation by demonstrating that Perlucin splice variants modulate the crystallisation of calcium carbonate. The identification of differentially behaving Perlucin variants may open a completely new perspective for the field of nacre biomineralisation.
Centre for Biomolecular Interactions Bremen, Department of Biology and Chemistry, University Bremen, Bremen, Germany.
Tanja
T
Dodenhof
Centre for Biomolecular Interactions Bremen, Department of Biology and Chemistry, University Bremen, Bremen, Germany.
Frank
F
Dietz
Department of Biochemistry and Molecular Biology, Rheinische Friedrich-Wilhelms- University, Bonn, Bonn, Germany.
Sebastian
S
Franken
Department Adhesives and Chemistry of Polymers, Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM), Bremen, Germany.
Ingo
I
Grunwald
Centre for Biomolecular Interactions Bremen, Department of Biology and Chemistry, University Bremen, Bremen, Germany.
Sørge
S
Kelm
D000818:Animals; D001499:Bayes Theorem; D015153:Blotting, Western; D019556:COS Cells; D002119:Calcium Carbonate / Q000737:chemistry*; D002522:Chlorocebus aethiops; D019295:Computational Biology; D003460:Crystallization; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D015180:Electrophoresis, Gel, Two-Dimensional; D004926:Escherichia coli; D049851:Gastropoda / Q000235:genetics* / Q000378:metabolism; D037102:Lectins / Q000235:genetics* / Q000378:metabolism; D058619:Maltose-Binding Proteins / Q000378:metabolism; D008957:Models, Genetic; D060734:Nacre / Q000378:metabolism*; D010802:Phylogeny; D010957:Plasmids / Q000235:genetics; D020033:Protein Isoforms / Q000235:genetics*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D017931:DNA Primers; D018076:DNA, Complementary; D037102:Lectins; D058619:Maltose-Binding Proteins; D060734:Nacre; D020033:Protein Isoforms; C403488:perlucin, Haliotis laevigata; D002119:Calcium Carbonate