Structure and function analysis of AtRALF peptide hormones: production of recombinant mutant RALF peptides in Escherichia coli and characterization of their biological activities

• Grant number: 12/09328-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2012
• End date: June 30, 2013
• Field of knowledge: Biological Sciences - Biochemistry - Molecular Biology
• Principal Investigator: Daniel Scherer de Moura
• Grantee: Paulo Henrique de Oliveira Ceciliato
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil

Abstract

RALF are plant secreted peptides of approximately 5kDa that have hormonal characteristics. RALF peptide hormones were isolated and identified for the first time in tobacco using the alkalinization assay and they are involved in cell elongation. Although their mechanism of action is still unknown, the presence of RALF peptides in all plant kingdom suggests a role in basic cellular process. The understanding of their mechanism of action, since they are related to cellular expansion, could be useful to manipulate and understand more plant development. Among the 37 RALF isoforms in the Arabidopsis genome (AtRALFs), only 9 of them show the characteristics essential for the RALF originally isolated from tobacco. Our group has produced the 9 RALFs in E. coli and their activities have been characterized. The size of the RALF peptides, around 50 amino acids, hinders studies of structure and function such as alanine scanning or multiple combinations of amino acid substitutions. Herein we are proposing a structure-functional analysis of the RALF peptides based on mutants produced in E. coli. The mutated peptides were defined based on the nine isoforms previously characterized. (AU)