TY - JOUR
T1 - The twenty-nine amino acid C-terminal cytoplasmic domain of poliovirus 3AB is critical for nucleic acid chaperone activity
AU - Gangaramani, Divya R.
AU - Eden, Elizabeth L.
AU - Shah, Manthan
AU - DeStefano, Jeffrey J.
N1 - Funding Information:
X-100 and 2.9% glycerol. The reactions were started by mixing We would like to thank Dr. Stephen Plotch (formerly of Wyeth-the FAM and DABCYL samples in a quartz cuvette (final con-Ayerst Research) for the plasmids for 3AB, Dr. Charles McHenry centrations 5 and 10 nM, for FAM and DABCYL DNAs, respec-(Univ. of Colarado) for the expression plasmid for HIV NC pro-tively). The excitation wavelength was 494 nm with a bandwidth tein and Dr. Gauri Nair for critical reading of the manuscript. of 5 nm. The emission bandwidth was 10 nm and the spectrum This work was supported by National Institutes of General was observed at 520 nm. The emission spectrum was taken every Medicine grant number GM051140 and undergraduate fellow-15 seconds for up to 16 minutes. An intensity ratio (Ir) was deter-ships from the Howard Hughes Medical Institute awarded to E. mined by dividing the peak intensity at a given time (It) by the Eden and M. Shah.
PY - 2010
Y1 - 2010
N2 - Poliovirus 3AB protein is the first picornavirus protein demonstrated to have nucleic acid chaperone activity. Further characterization of 3AB demonstrates that the C-terminal 22 amino acids (3B region (also referred to as VPg), amino acid 88-109) of the protein is required for chaperone activity, as mutations in this region abrogate nucleic acid binding and chaperone function. Protein 3B alone has no chaperone activity as determined by established assays that include the ability to stimulate nucleic acid hybridization in a primer-template annealing assay, helix-destabilization in a nucleic acid unwinding assay or aggregation of nucleic acids. In contrast, the putative 3AB C-terminal cytoplasmic domain (C terminal amino acids 81-109, 3B + the last 7 C-terminal amino acids of 3A, termed 3B+7 in this report) possesses strong activity in these assays, albeit at much higher concentrations than 3AB. The characteristics of several mutations in 3B+7 are described here, as well as a model proposing that 3B+7 is the site of the "intrinsic" chaperone activity of 3AB while the 3A N-terminal region (amino acids 1-58) and/or membrane anchor domain (amino acids 59-80) serve to increase the effective concentration of the 3B+7 region leading to the potent chaperone activity of 3AB.
AB - Poliovirus 3AB protein is the first picornavirus protein demonstrated to have nucleic acid chaperone activity. Further characterization of 3AB demonstrates that the C-terminal 22 amino acids (3B region (also referred to as VPg), amino acid 88-109) of the protein is required for chaperone activity, as mutations in this region abrogate nucleic acid binding and chaperone function. Protein 3B alone has no chaperone activity as determined by established assays that include the ability to stimulate nucleic acid hybridization in a primer-template annealing assay, helix-destabilization in a nucleic acid unwinding assay or aggregation of nucleic acids. In contrast, the putative 3AB C-terminal cytoplasmic domain (C terminal amino acids 81-109, 3B + the last 7 C-terminal amino acids of 3A, termed 3B+7 in this report) possesses strong activity in these assays, albeit at much higher concentrations than 3AB. The characteristics of several mutations in 3B+7 are described here, as well as a model proposing that 3B+7 is the site of the "intrinsic" chaperone activity of 3AB while the 3A N-terminal region (amino acids 1-58) and/or membrane anchor domain (amino acids 59-80) serve to increase the effective concentration of the 3B+7 region leading to the potent chaperone activity of 3AB.
KW - 3AB
KW - Nucleic acid chaperone
KW - Picornavirus
KW - Poliovirus
KW - Virus replication
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U2 - 10.4161/rna.7.6.13781
DO - 10.4161/rna.7.6.13781
M3 - Article
C2 - 21045553
AN - SCOPUS:78751674527
SN - 1547-6286
VL - 7
SP - 820
EP - 829
JO - RNA Biology
JF - RNA Biology
IS - 6
ER -