Structural Investigations of the Highly Flexible Recombinant Ribosomal Protein L12 from Thermotoga maritima
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Markus C. Wahl
Abstract
Ribosomal protein L7/L12, the only multicopy component of the ribosome, is involved in translation factor binding and in the ribosomal GTPase center. The gene for L7/L12 from Thermotoga maritima was cloned and the protein expressed at high levels in Escherichia coli. Purification of L7/L12 was achieved under nondenaturing conditions via heat treatment and two chromatographic steps. Circular dichroism melting profiles were monitored at 222 nm, showing the melting temperature of the protein at pH 7.5 around 110 C, compared to [tilde operator] 60 C for the highly homologous Escherichia coli protein. The unfolding was reversible and renaturation closely followed the path of the thermal melting. Dynamic light scattering, gel filtration chromatography, and crosslinking experiments suggested that under physiological buffer conditions Thermotoga maritima L7/L12 exists as a tetramer. The protein was crystallized under two conditions, yielding an orthorhombic (C222[1]) and a cubic (I2[(1)]3) space group with an estimated two and three to four L7/L12 molecules per asymmetric unit, respectively. The crystals contained the fulllength protein, and cryogenic buffers were developed which improved the mosaic spreads and the resolution limits. For the structure solution isoleucine was mutated to methionine at two separate positions, the mutant forms expressed as selenomethionine variants and crystallized.
Copyright © 2000 by Walter de Gruyter GmbH & Co. KG
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Articles in the same Issue
- Interaction of E. coli Single-Stranded DNA Binding Protein (SSB) with Exonuclease I. The Carboxy-Terminus of SSB Is the Recognition Site for the Nuclease
- p38/SAPK2-Dependent Gene Expression in Jurkat T Cells
- The First Laminin G-Type Domain in the SHBG-Like Region of Protein S Contains Residues Essential for Activation of the Receptor Tyrosine Kinase Sky
- Permutation of the Active Site Motif of Tryparedoxin 2
- Structural Investigations of the Highly Flexible Recombinant Ribosomal Protein L12 from Thermotoga maritima
- Polyhistidine-Tagged Hepatitis B Core Particles as Carriers of HIV-1/gp120 Epitopes of Different HIV-1 Subtypes
- In Vitro Evolution of Ligands for HCV-Specific Serum Antibodies
- Stability of Bacteriophage T4 Short Tail Fiber
- Analysis of the RNase T1 Mediated Cleavage of an Immobilized Gapped Heteroduplex via Fluorescence Correlation Spectroscopy
- Binding of Selenoprotein P to Heparin: Characterization with Surface Plasmon Resonance
- Biotin-Avidin Microplate Assay for the Quantitative Analysis of Enzymatic Methylation of DNA by DNA Methyltransferases
