Or you could ask the question, I have this restriction enzyme, at what regions on this plasmid will it cut?
你也可以这样问,我的这种限制性内切酶,会从质粒的哪个区域切开呢
In this case, this particular restriction enzyme cuts symmetrically like this, but not at the same point.
在我们这种情况下,这个限制性内切酶总是这样对称地切割,但两条链切割的位点不一样
This restriction enzyme was found in a natural source, it was found in a micro-organism called E.coli.
这个限制性内切酶源于自然界,是从名为大肠杆菌的微生物中发现的
That restriction enzyme, there is a restriction enzyme that does that and it's MST-3.
确实存在这种限制酶,叫MST-3
Most restriction enzyme also recognize symmetric sequences of DNA, GAATTC for example.
大多数限制性内切酶,也能识别DNA的对称序列,例如GAATTC
If I cut both the plasmid and my DNA of interest with the same restriction enzyme I'm going to end up with the same sticky ends on both molecules.
如果用同一种限制性内切酶,来切割质粒和我感兴趣的DNA,在两个分子上就能得到同样的粘性末端
If I took this same restriction enzyme and tried to cut the chromosomal DNA of a sickle patient, it wouldn't cut at that point because the wrong sequence is there.
而如果我用同样的限制酶,去切割病人的染色体DNA,那该酶是不会起作用的,因为基因序列不对
Restriction enzymes are just a kind of enzyme, enzymes are protein molecules that make a chemical reaction go faster, and the chemical reaction that restriction enzymes do is cutting DNA.
限制性内切酶是一种酶,而酶是加速化学反应的蛋白质分子,限制性内切酶加速的化学反应,是切割DNA
This particular restriction enzyme here recognizes this sequence,GAATTC.
这里的这种限制性内切酶,只识别序列GAATTC
Well one way you could do it is by saying 'if I have this one base pair difference then this sequence is going to be cut by a specific restriction enzyme that recognizes the sequence CTGAGGA'.
一种方法是通过考虑,"如果我有这个不同的碱基对,那该序列必然会,被特定的限制酶识别并切割,这个特定的限制酶能识别,CTGAGGA "
In a normal cell DNA that DNA in the normal cell - this DNA gets cut by the restriction enzyme, so the sickle gene ends up - so that hemoglobin gene ends up in two pieces.
一个正常细胞的DNA,正常细胞里的DNA,会被限制酶所剪切,因此镰状血红蛋白基因--,不对,是正常血红蛋白基因被切成两段
Well the first step would be to cut open the plasmid with a particular restriction enzyme, and then what if I take that same restriction enzyme and I cut up the DNA that I'm interested in.
第一步是用某种限制性内切酶把质粒切开,然后用同一种限制性内切酶,切出我想要的DNA
We're going to take a chromosomal DNA, we're going to digest it with this restriction enzyme, we're going to put it in this tube and run it on a gel, and we're going to see what results down here.
我们取一条染色体DNA,然后用限制酶进行分解,接着再放,在凝胶上进行电泳,之后看看结果如何
Now if I put them in contact with one another, the plasmid that's been opened and fragments of the DNA - special fragments that I've produced with the same restriction enzyme, they'll have the same sticky ends, they will naturally hybridize with one another.
如果我让它们互相接触,已经切开的质粒和DNA片段--,这DNA片段是我已用同种限制性内切酶,处理过的特别片段,这两者会有相同的粘性末端,它们会自然地相互杂交
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