Heterologous expression and initial characterization of recombinant RbcX protein from Thermosynechococcus elongatus BP-1 and the role of RbcX in RuBisCO assembly

• Published in: Acta biochimica polonica Vol. 55; no. 4; pp. 777 - 785
• Main Authors: Tarnawski, Miroslaw, Gubernator, Beata, Kolesinski, Piotr, Szczepaniak, Andrzej
• Format: Journal Article
• Language: English
• Published: Poland 01-01-2008
• Subjects: Amino Acid Sequence; Bacterial Proteins - chemistry; Bacterial Proteins - isolation & purification; Bacterial Proteins - metabolism; Base Sequence; Blotting, Western; Chromatography, Gel; DNA Primers; Electrophoresis, Polyacrylamide Gel; Escherichia coli; Molecular Chaperones - chemistry; Molecular Chaperones - isolation & purification; Molecular Chaperones - metabolism; Molecular Sequence Data; Plasmids; Recombinant Proteins - chemistry; Recombinant Proteins - isolation & purification; Recombinant Proteins - metabolism; Ribulose-Bisphosphate Carboxylase - metabolism; Sequence Homology, Amino Acid; Synechococcus - metabolism; Thermosynechococcus elongatus
• ISSN: 0001-527X; 1734-154X
• DOI: 10.18388/abp.2008_3040

In the cyanobacterial RuBisCO operon from Thermosynechococcus elongatus the rbcX gene is juxtaposed and cotranscribed with the rbcL and rbcS genes which encode large and small RuBisCO subunits, respectively. It has been suggested that the rbcX position is not random and that the RbcX protein could be a chaperone for RuBisCO. In this study, the RbcX protein from T. elongatus was overexpressed, purified and preliminary functional studies were conducted. The recombinant protein purified from Escherichia coli extracts was predominantly present in a soluble fraction in a dimeric form. Coexpression experiments have demonstrated that RbcX can mediate RbcL dimer (L(2)) formation, and that it is essential for the L(8) core complex assembly. This is the first characterization of the RbcX protein from a thermophilic organism.