PMID- 9679296
OWN - NLM
STAT- MEDLINE
DCOM- 19980811
LR  - 20190921
IS  - 0925-2738 (Print)
IS  - 0925-2738 (Linking)
VI  - 11
IP  - 2
DP  - 1998 Feb
TI  - Accurate quantitation of water-amide proton exchange rates using the 
      phase-modulated CLEAN chemical EXchange (CLEANEX-PM) approach with a Fast-HSQC 
      (FHSQC) detection scheme.
PG  - 221-6
AB  - Measurement of exchange rates between water and NH protons by magnetization 
      transfer methods is often complicated by artifacts, such as intramolecular NOEs, 
      and/or TOCSY transfer from C alpha protons coincident with the water frequency, 
      or exchange-relayed NOEs from fast exchanging hydroxyl or amine protons. By 
      applying the Phase-Modulated CLEAN chemical EXchange (CLEANEX-PM) spin-locking 
      sequence, 135 degrees (x) 120 degrees (-x) 110 degrees (x) 110 degrees (-x) 120 
      degrees (x) 135 degrees (-x) during the mixing period, these artifacts can be 
      eliminated, revealing an unambiguous water-NH exchange spectrum. In this paper, 
      the CLEANEX-PM mixing scheme is combined with Fast-HSQC (FHSQC) detection and 
      used to obtain accurate chemical exchange rates from the initial slope analysis 
      for a sample of 15N labeled staphylococcal nuclease. The results are compared to 
      rates obtained using Water EXchange filter (WEX) II-FHSQC, and spin-echo-filtered 
      WEX II-FHSQC measurements, and clearly identify the spurious NOE contributions in 
      the exchange system.
FAU - Hwang, T L
AU  - Hwang TL
AD  - Department of Radiology School of Medicine, Johns Hopkins University, Baltimore, 
      MD 21205-2195, USA.
FAU - van Zijl, P C
AU  - van Zijl PC
FAU - Mori, S
AU  - Mori S
LA  - eng
GR  - RR11115/RR/NCRR NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - Netherlands
TA  - J Biomol NMR
JT  - Journal of biomolecular NMR
JID - 9110829
RN  - 0 (Protons)
RN  - 059QF0KO0R (Water)
RN  - EC 3.1.31.1 (Micrococcal Nuclease)
SB  - IM
MH  - Magnetic Resonance Spectroscopy/*methods
MH  - Micrococcal Nuclease/*chemistry
MH  - Protons
MH  - Water/chemistry
EDAT- 1998/07/29 00:00
MHDA- 1998/07/29 00:01
CRDT- 1998/07/29 00:00
PHST- 1998/07/29 00:00 [pubmed]
PHST- 1998/07/29 00:01 [medline]
PHST- 1998/07/29 00:00 [entrez]
AID - 10.1023/a:1008276004875 [doi]
PST - ppublish
SO  - J Biomol NMR. 1998 Feb;11(2):221-6. doi: 10.1023/a:1008276004875.