title: High yield recombinant production of a self-assembling polycationic peptide for silica biomineralization.
abstract: We report the recombinant bacterial expression and purification at high yields of a polycationic oligopeptide, P5S3. The sequence of P5S3 was inspired by a diatom silaffin, a silica precipitating peptide. Like its native model, P5S3 exhibits silica biomineralizing activity, but furthermore has unusual self-assembling properties. P5S3 is efficiently expressed in Escherichia coli as fusion with ketosteroid isomerase (KSI), which causes deposition in inclusion bodies. After breaking the fusion by cyanogen bromide reaction, P5S3 was purified by cation exchange chromatography, taking advantage of the exceptionally high content of basic amino acids. The numerous cationic charges do not prevent, but may even promote counterion-independent self-assembly which in turn leads to silica precipitation. Enzymatic phosphorylation, a common modification in native silica biomineralizing peptides, can be used to modify the precipitation activity.
authors.affiliation: Institute of General Botany, Johannes Gutenberg University, Müllerweg 6, 55128 Mainz, Germany; Graduate School Materials Science in Mainz, Staudinger Weg 9, 55128 Mainz, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Zerfaß
authors.affiliation: Institute of Zoology, Johannes Gutenberg University, Müllerweg 6, 55128 Mainz, Germany.
authors.forename: Sandra
authors.initials: S
authors.lastname: Braukmann
authors.affiliation: Center for Electron Microscopy, University Hospital, Ziegelmühlenweg 1, 07743 Jena, Germany.
authors.forename: Sandor
authors.initials: S
authors.lastname: Nietzsche
authors.affiliation: Institute of General Botany, Johannes Gutenberg University, Müllerweg 6, 55128 Mainz, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Hobe
authors.affiliation: Institute of General Botany, Johannes Gutenberg University, Müllerweg 6, 55128 Mainz, Germany. Electronic address: paulsen@uni-mainz.de.
authors.forename: Harald
authors.initials: H
authors.lastname: Paulsen
mesh_terms: D017377:Diatoms / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D009842:Oligopeptides / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D009842:Oligopeptides; D011994:Recombinant Proteins; D012822:Silicon Dioxide
keywords: Ketosteroid isomerase fusion; Polycationic peptide; Silica biomineralization