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👑 今日主題：蛋白質的奧秘

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Science and technology 科技
Molecular Biology: Folding Stuff 分子生物學：折起來的東西
Shape determines a protein's function. Determining that shape, though, is tricky.
蛋白質的結構決定功能，而結構的判定卻很難。
ABOUT 120,000 types of protein molecule have yielded up their structures to science.
科學家已經瞭解了大約有120000種蛋白質分子的結構。
That sounds a lot, but it isn’t.
這看起來有很多，實則不然。
The techniques, such as X-ray crystallography and nuclear-magnetic resonance (NMR), which are used to elucidate such structures do not work on all proteins.
像X-射線晶體學，核磁共振（NMR）等一些用於分析蛋白質結構的技術，並非在所有蛋白質上都適用。
Some types are hard to produce or purify in the volumes required.
有些種類的蛋白質很難生產的或難以提純出所需要的量。
Others do not seem to crystallise at all—a prerequisite for probing them with X-rays.
其他類型的則無法結晶化—而這是利用X-ray檢測結構的先決條件。
As a consequence, those structures that have been determined include representatives of less than a third of the 16,000 known protein families.
這就導致，在16000個已知蛋白質家族的代表中，只有不超過三分之一的蛋白質的結構是已知的。
Researchers can build reasonable computer models for around another third, because the structures of these resemble ones already known.
基於已知曉的蛋白質的結構，研究人員可以針對另外1/3的蛋白質建立合理的電腦模型。
For the remainder, however, there is nothing to go on.
然而對剩餘的部分卻束手無策。
In addition to this lack of information about protein families, there is a lack of information about those from the species of most interest to researchers: Homo sapiens.
除蛋白質家族的資訊缺乏外，研究者對最讓他們感興趣的物種“智人”體內的蛋白質的瞭解也不多。
Only a quarter of known protein structures are human.
已知結構的蛋白質中，有1/4屬於人體內的蛋白質。
A majority of the rest come from bacteria.
其餘大部分來自於細菌。
This paucity is a problem, for in proteins form and function are intimately related.
因蛋白質的形態和功能密切相關，這一資訊的缺失是個問題。
A protein is a chain of smaller molecules, called amino acids, that is often hundreds or thousands of links long.
一個蛋白質分子是由較小分子所組成的分子鏈，稱之為氨基酸，蛋白質通常有成百上千條相連結。
By a process not well understood, this chain folds up, after it has been made, into a specific and complex three-dimensional shape.
通過一個尚未明確的加工過程，分子鏈生成會後摺疊成特定複雜的三維結構。
That shape determines what the protein does: acting as a channel, say, to admit a chemical into a cell; or as an enzyme to accelerate a chemical reaction; or as a receptor, to receive chemical signals and pass them on to a cell’s molecular machinery.
蛋白質的結構決定了他們的工作角色，充當通道，讓化學物質進入細胞，或者作為一種加速化學反應速度的酶；又或是作為受體接收化學信號並將其傳遞到細胞的分子機制內。
Almost all drugs work by binding to a particular protein in a particular place, thereby altering or disabling that protein’s function.
幾乎所有的藥物都通過與特定位置的特定蛋白質相結合而發揮作用，從而改變或限制蛋白質的功能。
Designing new drugs is easier if binding sites can be identified in advance.
如果可以預先得知靶位點，研發新藥物就較容易了。
But that means knowing the protein’s structure.
但這意味著要知道蛋白質的結構。
To be able to predict this from the order of the amino acids in the chain would thus be of enormous value.
利用氨基酸在分子鏈中的順序，預測出蛋白質的結構是有著極為重大意義的。
That is a hard task, but it is starting to be cracked.
這是一項艱巨的任務，但現在已經有了一定進展。
[原文出處: https://bit.ly/2I7CTyu]