RRC ID 35610
Author Singh P, Sharma L, Kulothungan SR, Adkar BV, Prajapati RS, Ali PS, Krishnan B, Varadarajan R.
Title Effect of signal peptide on stability and folding of Escherichia coli thioredoxin.
Journal PLoS One
Abstract The signal peptide plays a key role in targeting and membrane insertion of secretory and membrane proteins in both prokaryotes and eukaryotes. In E. coli, recombinant proteins can be targeted to the periplasmic space by fusing naturally occurring signal sequences to their N-terminus. The model protein thioredoxin was fused at its N-terminus with malE and pelB signal sequences. While WT and the pelB fusion are soluble when expressed, the malE fusion was targeted to inclusion bodies and was refolded in vitro to yield a monomeric product with identical secondary structure to WT thioredoxin. The purified recombinant proteins were studied with respect to their thermodynamic stability, aggregation propensity and activity, and compared with wild type thioredoxin, without a signal sequence. The presence of signal sequences leads to thermodynamic destabilization, reduces the activity and increases the aggregation propensity, with malE having much larger effects than pelB. These studies show that besides acting as address labels, signal sequences can modulate protein stability and aggregation in a sequence dependent manner.
Volume 8(5)
Pages e63442
Published 2013-1-1
DOI 10.1371/journal.pone.0063442
PII PONE-D-12-30695
PMID 23667620
PMC PMC3646739
MeSH Amino Acid Sequence Anilino Naphthalenesulfonates / metabolism Buffers Calorimetry, Differential Scanning Chromatography, Gel Circular Dichroism Electrophoresis, Polyacrylamide Gel Escherichia coli / metabolism* Guanidine / pharmacology Insulin / metabolism Molecular Sequence Data Protein Denaturation / drug effects Protein Folding* / drug effects Protein Refolding / drug effects Protein Sorting Signals* Protein Stability / drug effects Protein Structure, Quaternary Proteolysis / drug effects Recombinant Fusion Proteins / metabolism Spectrometry, Fluorescence Temperature Thioredoxins / chemistry* Thioredoxins / metabolism*
IF 2.74
Times Cited 26
Prokaryotes E. coli