抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Coherence transfer by isotropic mixing: Application to proton correlation spectroscopy

A two-dimensional nuclear overhauser experiment with pure absorption phase in four quadrants☆

https://zenodo.org/record/45375/files/article.pdf

Natural abundance nitrogen-15 NMR by enhanced heteronuclear spectroscopy

The widespread use of controlled molecular-level motion in key natural processes suggests that great rewards could come from bridging the gap between the present generation of synthetic molecular systems, which by and large rely upon electronic and chemical effects to carry out their functions, and the machines of the macroscopic world, which utilize the synchronized movements of smaller parts to perform specific tasks. This is a scientific area of great contemporary interest and extraordinary recent growth, yet the notion of molecular-level machines dates back to a time when the ideas surrounding the statistical nature of matter and the laws of thermodynamics were first being formulated. Here we outline the exciting successes in taming molecular-level movement thus far, the underlying principles that all experimental designs must follow, and the early progress made towards utilizing synthetic molecular structures to perform tasks using mechanical motion. We also highlight some of the issues and challenges that still need to be overcome.

Synthetic molecular motors and mechanical machines.

The stereoselective reaction of an allyl bromide with an aldehyde mediated by a low valency bismuth species was the key reaction in stereoselective syntheses of (4S,6R,8R,10S,16S)- and (4S,6R,8R,10S,16R)-4,6,8,10,16-pentamethyldocosanes. 13C NMR data for these compounds confirmed that the cuticular hydrocarbon isolated from the cane beetle Antitrogus parvulus was the (4S,6R,8R,10S,16S)-stereoisomer.

Total synthesis of a cuticular hydrocarbon from the cane beetle Antitrogus parvulus: confirmation of the relative stereochemistry

Real-time J scaling in carbon-13 NMR. II. An analysis of instrumental imperfections

Vicinal carbon-proton coupling constants have been measured for menthone by a new technique and show that the most stable rotamer is (1a) rather than (1b)

Proton-coupled carbon-13 nuclear magnetic resonance spectra from individual carbon sites in a molecule: the rotameric equilibrium in menthone

High-sensitivity, high-resolution NMR in inhomogeneous magnetic fields

The two-dimensional INEPT-INADEQUATE experiment gives correlation peaks for unprotonated carbons which show only half of the total available signal, because the enhanced 13C signal generated by polarization transfer is shared equally between protonated and unprotonated coupling partners by the double quantum filtration step. If precautions are taken to attenuate unwanted signals from protonated carbons, then the double quantum filtration step may be dispensed with, leaving a hydrogen-carbon-carbon relay sequence. This gives unidirectional coherence transfer, ensuring that the maximum possible signal is concentrated in a single cross-peak identifying the correlation between protonated and unprotonated carbons. By extending the basic HCC relay sequence to include an evolution period an enhanced 13C-13C COSY 2D spectrum may be produced, with the further advantage over the 2D INADEQUATE experiment that the range of 13C-13C coupling constants detectable is limited only by the available resolution.

Gareth A. Morris

Papers

Total synthesis of a cuticular hydrocarbon from the cane beetle Antitrogus parvulus: confirmation of the relative stereochemistry

Real-time J scaling in carbon-13 NMR. II. An analysis of instrumental imperfections

Proton-coupled carbon-13 nuclear magnetic resonance spectra from individual carbon sites in a molecule: the rotameric equilibrium in menthone

High-sensitivity, high-resolution NMR in inhomogeneous magnetic fields

An alternative to the 2D INADEQUATE experiment for detecting scalar coupling correlations between protonated and unprotonated carbons