The effect of 17O on the relaxation of an amide proton within a hydrogen bond

Halkides, Christopher J.; Redfield, Alfred G.

doi:10.1007/bf00182279

Cited by 4 publications

(4 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We find no evidence for an end capping either. It is difficult on the basis of the NOEs to unambiguously distinguish between ␣-helix and 3 10 -helix (Wüthrich, 1986) as the acceptor oxygens cannot be identified by NMR data (Halkides and Redfiels, 1995), but we observed certain C ␣ H i -NH iϩ4 , which imply the ␣-helical structure.…”

Section: Assignmentmentioning

confidence: 60%

Structure of the 1–36 Amino-Terminal Fragment of Human Phospholamban by Nuclear Magnetic Resonance and Modeling of the Phospholamban Pentamer

Pollesello

Annila

Ovaska

1999

Biophysical Journal

View full text Add to dashboard Cite

The structure of a 36-amino-acid-long amino-terminal fragment of phospholamban (phospholamban[1-36]) in aqueous solution containing 30% trifluoroethanol was determined by nuclear magnetic resonance. The peptide, which comprises the cytoplasmic domain and six residues of the transmembrane domain of phospholamban, assumes a conformation characterized by two alpha-helices connected by a turn. The residues of the turn are Ile18, Glu19, Met20, and Pro21, which are adjacent to the two phosphorylation sites Ser16 and Thr17. The proline is in a trans conformation. The helix comprising amino acids 22-36 is well determined (the root mean square deviation for the backbone atoms, calculated for a family of 18 nuclear magnetic resonance structures is 0.57 A). Recently, two molecular models of the transmembrane domain of phospholamban were proposed in which a symmetric homopentamer is composed of a left-handed coiled coil of alpha-helices. The two models differ by the relative orientation of the helices. The model proposed by,Simmerman et al. (H.K. Simmerman, Y.M. Kobayashi, J.M. Autry, and L.R. Jones, 1996, J. Biol. Chem. 271:5941-5946), in which the coiled coil is stabilized by a leucine-isoleucine zipper, is similar to the transmembrane pentamer structure of the cartilage oligomeric membrane protein determined recently by x-ray (V. Malashkevich, R. Kammerer, V Efimov, T. Schulthess, and J. Engel, 1996, Science 274:761-765). In the model proposed by Adams et al. (P.D. Adams, I.T. Arkin, D.M. Engelman, and A.T. Brunger, 1995, Nature Struct. Biol. 2:154-162), the helices in the coiled coil have a different relative orientation, i.e., are rotated clockwise by approximately 50 degrees. It was possible to overlap and connect the structure of phospholamban[1-36] derived in the present study to the two transmembrane pentamer models proposed. In this way two models of the whole phospholamban in its pentameric form were generated. When our structure was connected to the leucine-isoleucine zipper model, the inner side of the cytoplasmic domain of the pentamer (where the helices face one another) was lined by polar residues (Gln23, Gln26, and Asn30), whereas the five Arg25 side chains were on the outer side. On the contrary, when our structure was connected to the other transmembrane model, in the inner side of the cytoplasmic domain of the pentamer, the five Arg25 residues formed a highly charged cluster.

show abstract

Section: Assignmentmentioning

confidence: 60%

Structure of the 1–36 Amino-Terminal Fragment of Human Phospholamban by Nuclear Magnetic Resonance and Modeling of the Phospholamban Pentamer

Pollesello

Annila

Ovaska

1999

Biophysical Journal

View full text Add to dashboard Cite

show abstract

“…No significant difference could be observed between labelled and unlabelled samples, in spite of the fact that the hydrogen bond of the peptide group of Gly 13 to the b-phosphate is shorter than a typical one (d % 10.5 ppm). It was suggested [733] that for macromolecules in which an oxygen atom is the acceptor of a hydrogen bond, dipolar coupling between 17 O and hydrogen may be observable only for extremely short hydrogen bonds.…”

Section: Oxygen Quadrupolar Effects On Other Nucleimentioning

confidence: 99%

“…Halkides and Redfield [733] investigated in detail the effect of 17 O on the relaxation of a peptide proton which participates in a hydrogen bond. The rate of single-quantum transverse relaxation of the peptide proton is a function of the dipolar coupling to 15 N; therefore, this relaxation mechanism is in competition with dipolar broadening due to a more distant 17 O nucleus.…”

Section: Oxygen Quadrupolar Effects On Other Nucleimentioning

confidence: 99%

“…Therefore, the rate of multiple-quantum relaxation might be more sensitive to the presence of 17 O. The relaxation rates of the multiple-quantum coherence for the peptide hydrogen of Gly 13 in ras p21ÁGDP were determined [733] in the presence and absence of 17 O labeling in the b-phosphate of GDP. No significant difference could be observed between labelled and unlabelled samples, in spite of the fact that the hydrogen bond of the peptide group of Gly 13 to the b-phosphate is shorter than a typical one (d % 10.5 ppm).…”

Section: Oxygen Quadrupolar Effects On Other Nucleimentioning

confidence: 99%

See 1 more Smart Citation