Correlation between ^3hJ_NC‘ and Hydrogen Bond Length in Proteins

Abstract

Establishing a quantitative relationship between backbone-backbone hydrogen-bond (H-bond) length observed in protein crystal structures and recently observed 3h J NC′ couplings across such bonds is limited by the coordinate precision of the X-ray structure. For an immunoglobulin binding domain of streptococcal protein G, very high-resolution X-ray structures are available. It is demonstrated that over the small range of N-O H-bond lengths (2.8-3.3 Å) for which 3h J NC′ couplings are observable, the 32 measured 3h J NC′ values can be fit to: 3h J NC′ ) -59000 exp(-4R NO ) ( 0.09 Hz, or R NO ) 2.75 -0.25 ln(-3h J NC′ ) ( 0.06 Å. Backbone amide to side-chain carboxyl hydrogen bonds were also investigated, and the measured 3h J NC′ values tend to be smaller than expected from their crystallographically determined H-bond lengths. The sign of 3h J NC′ , determined from a zero-quantum/double-quantum experiment, is found to be the same as that of the 1 J NH coupling, i.e., negative.

Correlation of the Sweetness of Variants of the Protein Brazzein with Patterns of Hydrogen Bonds Detected by NMR Spectroscopy

“…6D) Fig. 6, changes in trans-hydrogen bond couplings can be evaluated in terms of changes in hydrogen bond distances (17). Fig.…”

“…Regions of high mobility include loop 43 along with the C-terminal end of strand III and the N-terminal end of strand II and also regions of the disordered loop (residues 13,[17][18] including the start of the ␣-helix (residue 19). In the terminal regions, residues 4 and 54 exhibit high mobility, as well as residue 53 in the R33A and D50A variants.…”

“…The program CHIFIT (38) was used to quantify the chemical shifts and intensities of peaks accurately. Measurements from this program were used for hydrogen bond calculations as described earlier (16,17,39).…”

“…Although trans-hydrogen bond 15 N- 13 C NMR scalar coupling constants are very small (͉ 3h J NCЈ ͉ Ͻ 1 Hz), methods have been developed recently (15)(16)(17)(18) which permit their detection in small proteins (Ͻ30 kDa). These methods employ constant time, long range, two-or three-dimensional NMR correlation experiment that identifies connectivities among backbone 1 H N , 15 N, and 13 CЈ atoms (HNCO) 1 pulse sequences, either without or with the application of the transverse optimized spectroscopy (TROSY) technique (19) for increased sensitivity.…”

A review with comprehensive data on experimental indirect scalar NMR spin–spin coupling constants across hydrogen bonds

“…[29 -41] Bax et al determined that 3h J NC is negative and also found an exponential relationship between 3h J NC and R NO (or d N· · ·O , in Å, from X-ray structures): 3h J NC = −59 000 exp(−4R NO ) ±0.09 Hz. [31] Li et al have studied pressure effects on protein G (from 30 to 2000 bar) on 3h J NC ; [32] since the previous equation related 3h J NC and R NO , the difference in coupling constants suggest a compaction of the helix ends and an increase of the helix pitch.…”