A ribosomal misincorporation of Lys for Arg in human triosephosphate isomerase expressed in Escherichia coli gives rise to two protein populations.

ABSTRACT: We previously observed that human homodimeric triosephosphate isomerase (HsTIM) expressed in Escherichia coli and purified to apparent homogeneity exhibits two significantly different thermal transitions. A detailed exploration of the phenomenon showed that the preparations contain two proteins; one has the expected theoretical mass, while the mass of the other is 28 Da lower. The two proteins were separated by size exclusion chromatography in 3 M urea. Both proteins correspond to HsTIM as shown by Tandem Mass Spectrometry (LC/ESI-MS/MS). The two proteins were present in nearly equimolar amounts under certain growth conditions. They were catalytically active, but differed in molecular mass, thermostability, susceptibility to urea and proteinase K. An analysis of the nucleotides in the huma

SUBMITTER: Aguirre B 

PROVIDER: S-EPMC3125179 | biostudies-literature | 2011

REPOSITORIES: biostudies-literature