The silica mineralisation properties of synthetic Silaffin-1A1 (synSil-1A1).
Org Biomol Chem
; 20(16): 3387-3396, 2022 04 20.
Article
em En
| MEDLINE
| ID: mdl-35362502
ABSTRACT
The synthetic monodisperse pentadecapeptide synSil-1A1 is a representative of the microdisperse mixture of the native silaffin natSil-1A1 produced by the diatom Cylindrotheca fusiformis. The octaphosphorylated zwitterionic synSil-1A1 is able to mineralise silica under slightly acidic conditions at pH 5.5, which is the physiologically relevant pH range assumed. Like the posttranslational modifications of the native silaffins, synSil-1A1 is functionalised on all four lysine and phosphorylated on all seven serine residues. We describe the synthesis of a trimethyl-δ-hydroxy-L-lysine building block, the incorporation of this choline-type amino acid in peptide synthesis and its phosphorylation, together with all further posttranslational modifications observed in the native silaffins. Quantitative structure-activity relationships from silicification experiments at high dilution reveal the unique mineralisation properties of the hyperphosphorylated peptide as a single substance and in interaction with long-chain polyamines (LCPA). Diffusion-ordered spectroscopy (DOSY) experiments reveal the formation of polyelectrolyte complexes (PEC) between synSil-1A1 and long-chain polyamines, which promotes the silicification process. The microdroplets have an overall balanced ratio of 100-150 cationic and the same number of anionic charges. The unique zwitterionic synSil-1A1 confirms the prevailing molecular model of biosilicification and validates it with quantitative data based on a single phosphopeptide species, avoiding the usual unphysiologically high concentrations of phosphate of many previous in vitro silicification experiments.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Diatomáceas
/
Dióxido de Silício
Idioma:
En
Revista:
Org Biomol Chem
Assunto da revista:
BIOQUIMICA
/
QUIMICA
Ano de publicação:
2022
Tipo de documento:
Article
País de afiliação:
Alemanha