TY - JOUR
T1 - Site-selective intramolecular hydrogen-bonding interactions in phosphorylated serine and threonine dipeptides
AU - Lee, Kyung Koo
AU - Kim, Eunmyung
AU - Joo, Cheonik
AU - Song, Jaewook
AU - Han, Hogyu
AU - Cho, Minhaeng
PY - 2008/12/25
Y1 - 2008/12/25
N2 - To study the phosphorylation effect on the peptide conformation, we carried out nuclear magnetic resonance (NMR), circular dichroism (CD), Fourier transform (FT)-IR, and vibrational circular dichroism (VCD) experiments with serine and threonine dipeptides (SD and TD) and their phosphorylated ones (pSD and pTD). It is found that both unphosphorylated and phosphorylated serine and threonine dipeptides adopt two conformations, polyproline II (PII) and β-strand. The pH-dependent NMR study shows that the side-chain dianionic phosphoryl group can form direct intramolecular hydrogen bonds with the backbone amide protons at both the acetyl and amide ends of pTD, but only at the acetyl end of pSD. Temperature- and pH-dependent CD studies reveal that, unlike pSD, pTD undergoes conformational transition from PII to β-strand upon double ionization of the phosphoryl group. The subtle but distinct differences between pTD and pSD in site-selective intramolecular hydrogen-bonding interaction and charge-dependent conformational transition may sometimes become significant when choosing between serine and threonine for the conformational control of peptides and proteins by phosphorylation.
AB - To study the phosphorylation effect on the peptide conformation, we carried out nuclear magnetic resonance (NMR), circular dichroism (CD), Fourier transform (FT)-IR, and vibrational circular dichroism (VCD) experiments with serine and threonine dipeptides (SD and TD) and their phosphorylated ones (pSD and pTD). It is found that both unphosphorylated and phosphorylated serine and threonine dipeptides adopt two conformations, polyproline II (PII) and β-strand. The pH-dependent NMR study shows that the side-chain dianionic phosphoryl group can form direct intramolecular hydrogen bonds with the backbone amide protons at both the acetyl and amide ends of pTD, but only at the acetyl end of pSD. Temperature- and pH-dependent CD studies reveal that, unlike pSD, pTD undergoes conformational transition from PII to β-strand upon double ionization of the phosphoryl group. The subtle but distinct differences between pTD and pSD in site-selective intramolecular hydrogen-bonding interaction and charge-dependent conformational transition may sometimes become significant when choosing between serine and threonine for the conformational control of peptides and proteins by phosphorylation.
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U2 - 10.1021/jp803285x
DO - 10.1021/jp803285x
M3 - Article
C2 - 19049417
AN - SCOPUS:58149166574
VL - 112
SP - 16782
EP - 16787
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
SN - 1520-6106
IS - 51
ER -