Proteins, you will remember, are the workhorses of all living systems; as many as a hundred million of them may be busy in any cell at any moment. That's a lot of activity to try to figure out.
你可能記得，蛋白質(zhì)是所有生命系統(tǒng)的役馬：每個(gè)細(xì)胞中都有多達(dá)1億計(jì)的蛋白質(zhì)在一刻不停地工作。它們的活動(dòng)如此之多，令人無法捉摸。
Worse, proteins' behavior and functions are based not simply on their chemistry, as with genes, but also on their shapes. To function, a protein must not only have the necessary chemical components, properly assembled, but then must also be folded into an extremely specific shape. "Folding" is the term that's used, but it's a misleading one as it suggests a geometrical tidiness that doesn't in fact apply. Proteins loop and coil and crinkle into shapes that are at once extravagant and complex. They are more like furiously mangled coat hangers than folded towels.
更糟糕的是，蛋白質(zhì)的行為方式和功能不僅像基因那樣取決于它們的化學(xué)性質(zhì)，而且取決于它們的形狀。若要具有正常功能，一個(gè)蛋白質(zhì)必須具備以恰當(dāng)?shù)姆绞浇M合在一起的化學(xué)成分，之后還必須折疊成一種非常特別的形狀。這里所使用的“折疊”這個(gè)詞實(shí)際上是一種容易引起混淆的概念，仿佛是幾何學(xué)意義上的齊整的意思，其實(shí)并不是這樣的。蛋白質(zhì)卷成的和盤折成的形狀又隨意又復(fù)雜，與其說它們像拆疊好的毛巾，倒不如說它們像亂作一團(tuán)的衣架。
Moreover, proteins are (if I may be permitted to use a handy archaism) the swingers of the biological world. Depending on mood and metabolic circumstance, they will allow themselves to be phosphorylated, glycosylated, acetylated, ubiquitinated, farneysylated, sulfated, and linked to glycophosphatidylinositol anchors, among rather a lot else. Often it takes relatively little to get them going, it appears. Drink a glass of wine, as Scientific American notes, and you materially alter the number and types of proteins at large in your system. This is a pleasant feature for drinkers, but not nearly so helpful for geneticists who are trying to understand what is going on.
除此以外，蛋白質(zhì)還是生物世界的登徒子（請(qǐng)?jiān)试S我使用一個(gè)信手得來的古詞）。根據(jù)一時(shí)的興起及新陳代謝的狀況，它們會(huì)隨心所欲地磷硫酸化、糖基化、乙酰化、泛素化、硫酸鹽化，以及其他許多種不同的變化。往往，似乎并不需要花費(fèi)太大力氣就會(huì)使它們發(fā)生變化。飲一杯酒，正如《科學(xué)美國(guó)人》所說的那樣，你就會(huì)極大地改變你整個(gè)系統(tǒng)內(nèi)的蛋白質(zhì)的數(shù)量和種類。對(duì)于癮君子來說，這倒是令人高興的一件事，但是對(duì)那些試圖搞清楚這一切是怎么發(fā)生的遺傳學(xué)家來說，卻根本沒有幫助。
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