英國(guó)牛津大學(xué)的科學(xué)家日前解開(kāi)了一個(gè)困擾科學(xué)界達(dá)半個(gè)世紀(jì)之久的謎團(tuán)：糖分子如何改變自己的形狀及其背后存在的機(jī)理。
糖分子是世界上最豐富的有機(jī)分子,，不僅在人類(lèi)飲食中很常見(jiàn),，而且還能以纖維素和甲殼素的形式存在于植物和昆蟲(chóng)細(xì)胞中。早在1955年,，科學(xué)家就從化學(xué)上確認(rèn)了糖分子的變形現(xiàn)象,，并將其命名為異頭效應(yīng)，不過(guò)他們認(rèn)為這是因?yàn)橛兴蚱渌镔|(zhì)存在并產(chǎn)生影響的結(jié)果,。
為了證實(shí)這個(gè)理論,，在戴維斯教授和西蒙斯教授領(lǐng)導(dǎo)下，英國(guó)牛津大學(xué)兩個(gè)團(tuán)隊(duì)的研究人員將糖氣化,，使之與其他所有物質(zhì)分離,，然后監(jiān)測(cè)它們的表現(xiàn)。研究發(fā)現(xiàn),，分離出來(lái)的糖分子仍然保持著不尋常的化學(xué)外觀,。
戴維斯教授解釋說(shuō)：“異頭效應(yīng)是有機(jī)化學(xué)的基礎(chǔ)，但是直到如今,，我們對(duì)它的了解還非常有限,。如果糖不能改變形狀，那么我們的生活將完全不同,，也許很多生物進(jìn)程就再也不會(huì)起作用了,。”
他還表示，糖很可能將成為制造業(yè)的未來(lái),，因?yàn)槔锰欠肿涌梢陨a(chǎn)化學(xué)品,，其可用性遠(yuǎn)遠(yuǎn)大于石油，而且人類(lèi)也不太可能把地球上的糖耗盡,。從理論上來(lái)說(shuō),，化學(xué)家?guī)缀蹩梢詫⑻侵瞥扇魏斡袡C(jī)分子，因此人類(lèi)應(yīng)該可以利用糖去取代石油,，并生產(chǎn)出需要利用石油生產(chǎn)的所有產(chǎn)品,。
糖對(duì)醫(yī)藥的影響可能也同樣巨大，人們對(duì)糖的了解遠(yuǎn)不及對(duì)DNA和蛋白質(zhì)之類(lèi)分子的了解,。戴維斯教授指出：“將糖生物學(xué)轉(zhuǎn)化為醫(yī)學(xué)是生物學(xué)的最新前沿,。但一旦能夠達(dá)成，我們將獲得巨大的回報(bào),。”（生物谷Bioon.com）
生物谷推薦原文出處：
Nature doi:10.1038/nature09693
Sensing the anomeric effect in a solvent-free environment
Emilio J. Cocinero,Pierre ?ar?abal,Timothy D. Vaden,John P. Simons& Benjamin G. Davis
The anomeric effect is a chemical phenomenon1, 2, 3, 4, 5, 6, 7, 8, 9 that refers to an observed stabilization10 of six-membered carbohydrate rings when they contain an electronegative substituent at the C1 position of the ring. This stereoelectronic effect influences the three-dimensional shapes of many biological molecules. It can be manifested not only in this classical manner involving interaction of the endocyclic oxygen atom (O5) found in such sugars with the C1 substituent (endo-anomeric effect) but also through a corresponding interaction of the electronegative exocyclic substituent with O5 (exo-anomeric effect). However, the underlying physical origin(s) of this phenomenon is still not clear1, 3, 4, 11, 12, 13, 14. Here we show, using a combination of laser spectroscopy and computational analysis, that a truncated peptide motif can engage the two anomers of an isolated sugar in the gas phase, an environment lacking extraneous factors which could confound the analysis. (Anomers are isomers that differ in the orientation of the substituent at C1.) Complexes formed between the peptide and the α- or β-anomers of d-galactose are nearly identical structurally; however, the strength of the polarization of their interactions with the peptide differs greatly. Natural bond order calculations support this observation, and together they reveal the dominance of the exo- over the endo-anomeric effect. As interactions between oxygen atoms at positions C1 and C2 (O1 and O2, respectively) on the pyranose ring can alter the exo/endo ratio of a carbohydrate, our results suggest that it will be important to re-evaluate the influence, and biological effects, of substituents at position C2 in sugars.
