TY - JOUR
T1 - A compare-and-contrast NMR dynamics study of two related RRMs
T2 - U1A and SNF
AU - Dekoster, Gregory T.
AU - Delaney, Kimberly J.
AU - Hall, Kathleen B.
N1 - Funding Information:
This study made use of the National Magnetic Resonance Facility at Madison (NMRFAM), which is supported by National Institutes of Health grants P41RR02301 (Biomedical Research Training Program/National Center for Research Resources) and P41GM10399 (National Institute of General Medical Sciences). We thank Dr. Marco Tonelli for help at NMRFAM. This work was supported by the National Institutes of Health (1R01 GM096444 to K.B.H.).
PY - 2014/7/1
Y1 - 2014/7/1
N2 - The U1A/U2B″/SNF family of small nuclear ribonucleoproteins uses a phylogenetically conserved RNA recognition motif (RRM1) to bind RNA stemloops in U1 and/or U2 small nuclear RNA (snRNA). RRMs are characterized by their α/β sandwich topology, and these RRMs use their β-sheet as the RNA binding surface. Unique to this RRM family is the tyrosine-glutamine- phenylalanine (YQF) triad of solvent-exposed residues that are displayed on the β-sheet surface; the aromatic residues form a platform for RNA nucleobases to stack. U1A, U2B″, and SNF have very different patterns of RNA binding affinity and specificity, however, so here we ask how YQF in Drosophila SNF RRM1 contributes to RNA binding, as well as to domain stability and dynamics. Thermodynamic double-mutant cycles using tyrosine and phenylalanine substitutions probe the communication between those two residues in the free and bound states of the RRM. NMR experiments follow corresponding changes in the glutamine side-chain amide in both U1A and SNF, providing a physical picture of the RRM1 β-sheet surface. NMR relaxation and dispersion experiments compare fast (picosecond to nanosecond) and intermediate (microsecond-to-millisecond) dynamics of U1A and SNF RRM1. We conclude that there is a network of amino acid interactions involving Tyr-Gln-Phe in both SNF and U1A RRM1, but whereas mutations of the Tyr-Gln-Phe triad result in small local responses in U1A, they produce extensive microsecond-to-millisecond global motions throughout SNF that alter the conformational states of the RRM.
AB - The U1A/U2B″/SNF family of small nuclear ribonucleoproteins uses a phylogenetically conserved RNA recognition motif (RRM1) to bind RNA stemloops in U1 and/or U2 small nuclear RNA (snRNA). RRMs are characterized by their α/β sandwich topology, and these RRMs use their β-sheet as the RNA binding surface. Unique to this RRM family is the tyrosine-glutamine- phenylalanine (YQF) triad of solvent-exposed residues that are displayed on the β-sheet surface; the aromatic residues form a platform for RNA nucleobases to stack. U1A, U2B″, and SNF have very different patterns of RNA binding affinity and specificity, however, so here we ask how YQF in Drosophila SNF RRM1 contributes to RNA binding, as well as to domain stability and dynamics. Thermodynamic double-mutant cycles using tyrosine and phenylalanine substitutions probe the communication between those two residues in the free and bound states of the RRM. NMR experiments follow corresponding changes in the glutamine side-chain amide in both U1A and SNF, providing a physical picture of the RRM1 β-sheet surface. NMR relaxation and dispersion experiments compare fast (picosecond to nanosecond) and intermediate (microsecond-to-millisecond) dynamics of U1A and SNF RRM1. We conclude that there is a network of amino acid interactions involving Tyr-Gln-Phe in both SNF and U1A RRM1, but whereas mutations of the Tyr-Gln-Phe triad result in small local responses in U1A, they produce extensive microsecond-to-millisecond global motions throughout SNF that alter the conformational states of the RRM.
UR - http://www.scopus.com/inward/record.url?scp=84903984754&partnerID=8YFLogxK
U2 - 10.1016/j.bpj.2014.05.026
DO - 10.1016/j.bpj.2014.05.026
M3 - Article
C2 - 24988355
AN - SCOPUS:84903984754
VL - 107
SP - 208
EP - 219
JO - Biophysical Journal
JF - Biophysical Journal
SN - 0006-3495
IS - 1
ER -