Chemistry Reference
In-Depth Information
Fig. 2 2D
13
C DQ/SQ NMR correlation of the fully hydrated [
13
C
6
,
15
N]-Leu-BR sample using a
Bruker AV-III 600 MHz wide-bore spectrometer with an MAS rate of 8 kHz (a) and the protein
function assay through detection of the M state signal and proton pumping cycle signal at 412nm
(b) and 456nm (c) by optical dynamic spectroscopy, respectively
3.2 Three-Dimensional Structure Determination
Determination of membrane proteins and amyloid fiber structures is still a frontier
of structural biology. Over the last few years, much progress has been made in
various areas from NMR methodology to sample preparation in order to reduce the
dipolar truncation, establish reliable short and long range distance constraints, and
improve spectral linewidths and resolution for a full structure determination. The
Baldus group has established a method to probe through-space (
1
H,
1
H) contacts of
protonated solid-phase systems in high spectral resolution [
125
]. The so-called
CHHC/NHHC experiment was first demonstrated to solve a micro-crystalline Crh
protein [
126
], and then successfully applied to the membrane bound potassium
channel KcsA-Kv1.3 to study its structure activation and inhibition [
7
]. By combing
the
1
H
1
H distance restraints, chemical shift changes, and molecular modeling, they
have obtained the first membrane protein structure by SSNMR, as shown in Fig.
3
,
which provides a deep understanding of channel activation and inhibition [
7
].
Full or nearly full SSNMR spectral assignments have not been achieved on
membrane proteins for quite some time due to the signal overlapping and fast
longitudinal and transverse relaxation which causes line broadening and signal
intensity loss in many correlation experiments, impeding the pace of SSNMR
structure determination of large membrane proteins and protein-complexes.
Recently, the Oschkinat group has proposed a novel specific labeling scheme by
...
