分子生物学入门-病毒感染原理

分子生物学入门-病毒感染原理

Molecular Biology Primer – How Viruses Work

Welcome to our molecular biology primer. For those who have not initiated in molecular biology, this is not meant to be a comprehensive review of every aspect of molecular biology.

欢迎参加我们的分子生物学入门讲座。对于那些尚未开始分子生物学学习的人，本讲座并不意味着对分子生物学的各个方面都有全面的评论。

Every cell has a nucleus, and it is in the nucleus that you have DNA. DNA codes for the different types of proteins that are used in the nucleus, and DNA is basically two strings interwoven, called a double helix. They are made up of a string of nucleotides, and those nucleotides are arranged in certain codes. Those codes tell you exactly what your protein is going to be when you are done.

每个细胞都有一个核，而您的DNA就是在核中。 DNA编码核中使用的不同类型的蛋白质，而DNA基本上是两根交织在一起的线，称为双螺旋。它们由一串核苷酸组成，并且这些核苷酸以某些代码排列。这些代码准确地告诉您完成后蛋白质的成分。

A T G and C are the letters that the nucleus will use as a code that will be translated into proteins and protein synthesis. So in the DNA, because it is double-stranded, if on one side there is an A, then the other side must be binding to a T. That’s how they keep it straight on one side. There is a G on the other side, there is a C. So if you know what one strands code is, you will be able to figure out what the other code is.

A, T, G和C是原子核将用作编码的字母，这些字母将被翻译成蛋白质和蛋白质合成。因此在DNA中，因为它是双链的，所以如果在一侧有一个A，那么另一侧必须与T结合。这就是他们如何使其在一侧保持笔直。另一面有一个G，一个C。因此，如果您知道一个代码串是什么，那么您将能够弄清楚另一个代码是什么。

So there’s also something about these DNA molecules that is important as well. On every single one of these nucleotides, there is one less oxygen than would normally be. That’s why it’s known as deoxyribonucleic acid. That’s important to understand because when we get out to the cytoplasm, which is the rest of the cell and inside the cell, but not in the nucleus, instead of using DNA, we’re going to be using RNA.

因此，关于这些DNA分子也有一些重要的内容。在这些核苷酸的每一个上，氧比通常少一。这就是为什么它被称为脱氧核糖核酸。理解这一点很重要，因为当我们到达细胞质时，即细胞的其余部分和细胞内部，而不是细胞核中，而不是使用DNA，我们将使用RNA。

RNA is exactly the same as DNA except for two major areas. RNA will use exactly the same letters, except it will not use a T, it will use a U, so it’s AUGC. U stands for uracil. The other thing about it is that in that area where there is no oxygen, there actually is an oxygen, and that’s why it’s known as ribonucleic acid. And this is known as deoxyribonucleic acid. So DNA is completely different than RNA in that sense.

除了两个主要方面外，RNA与DNA完全相同。 RNA将使用完全相同的字母，除了不使用T，将使用U，所以它是AUGC。 U代表尿嘧啶。另一件事是在那个没有氧的区域，实际上有一个氧，这就是为什么它被称为核糖核酸的原因。这就是所谓的脱氧核糖核酸。因此，DNA在这个意义上与RNA完全不同。

But in another sense, it’s using pretty much the same language. It’s using the language of nucleotides. The language here is nucleotides in the nucleus, and the language here is in the script if you will, of nucleotides, it is nucleotides that create the code.

但换句话说，它使用的语言几乎相同。它使用核苷酸的语言。这里的语言是原子核中的核苷酸，如果您要创建核苷酸，则这里的语言在脚本中，它是核苷酸来创建代码。

RNA generally speaking is not double-stranded; it is only single-stranded. So what happens here is that this is the master blueprint. That is the DNA. And what happens is that this DNA opens up, and I’ll show you here what it looks like. So imagine this is a strand here of DNA. It opens up and there is a direction to these ends. (Just go with me on this one.) One is known as the five-prime-end, and another is known as the three-prime-end. Then it flips around the other one has it arranged so that this side is the five-prime end and the other side is the three-prime-end.

一般来说，RNA不是双链的。它仅是单链的。因此，这里发生的是这是主蓝图。那就是DNA。发生的事情是这种DNA打开了，在这里我将向您展示它的外观。因此，可以想象这是DNA的一小部分。它打开了，并为这些目的指明了方向。 （跟我一起看。）一个被称为五端，另一个被称为三端。然后，它绕另一端翻转，使它的另一侧为五端，另一侧为三端。

So what happens is there’s an enzyme called RNA polymerase. Anytime I say ASE at the end of anything, it’s an enzyme, and it’s a protein enzyme generally speaking. RNA polymerase is the enzyme that polymerizes RNA together. So here we have this RNA polymerase that’s on the DNA, and it’s traveling in this direction, and as it goes over the different nucleotides, boom-boom-boom-boom-boom, the different nucleotides and this is all happening in the nucleus, it starts to pull in different nucleotides that are available to make a long string of RNA.

因此，发生了一种叫做RNA聚合酶的酶。任何时候我说ASE时，它都是一种酶，而且通常来说，它是一种蛋白质酶。 RNA聚合酶是将RNA聚合在一起的酶。因此，在这里，我们有一种在DNA上的RNA聚合酶，它沿着这个方向行进，随着它越过不同的核苷酸，臂杆-臂杆-臂杆-臂杆-臂杆，不同的核苷酸，这些都发生在核中，它开始引入不同的核苷酸，这些核苷酸可用于制造一长串RNA。

Because we’re going from the language of nucleotides, nucleotides being the language here, because we’re going from nucleotides again back to nucleotides, that is not a change in the language of the code. That is simply a transcription of the code. It’s like we’re photocopying almost, so transcription is the term that is used when you go from nucleotides to nucleotides.

因为我们要从核苷酸的语言出发，所以核苷酸是这里的语言，因为我们要从核苷酸再回到核苷酸，所以这不是代码语言的变化。那只是代码的转录。就像我们几乎要复印一样，因此转录是指从核苷酸到核苷酸时使用的术语。

When you’re going from the nucleus, information is coming out into the cytoplasm; you must transfer from DNA into RNA. And generally speaking in human cells, there’s no way to really go from RNA back to DNA. This is a unidirectional thing. So in other words, the code is always kept the same, generally speaking. It is copied in the process of transcription, and you go from a copy of the DNA, making a copy of the RNA.

当您从细胞核出发时，信息正在进入细胞质。您必须从DNA转移到RNA。一般来说，在人类细胞中，没有办法真正地从RNA回到DNA。这是单向的。因此，换句话说，通常来说，代码始终保持不变。它在转录过程中被复制，您从DNA的副本中复制出RNA的副本。

Here we have the RNA. There’s something that happens to the RNA. There is a five-prime-end and there’s also a 3-prime end, and what happens is they put a cap on the beginning of the 5-prime-end to protect it, so it doesn’t start to dissolve. Then there’s also, what we know, is a poly-A tail at the 3-prime-end.

这是RNA。 RNA发生了一些变化。有一个5素数的末端，也有一个3素数的末端，发生的事情是，他们在5素数的末端的开始处设置了上限以保护它，因此它不会开始溶解。然后，我们知道，在3素数末端还有一个poly-A尾巴。

This RNA with a five-prime cap and a 3-prime poly-A tail is known as a special type of RNA, known as messenger RNA. Why is it called messenger? Because it’s sending out a message from the nucleus into the cytoplasm about what needs to happen next. In other words, it has the grand blueprint for the entire cell, and it’s saying here are the plans for this portion of the cell that I want to build, and here is the message that’s coming from the central portion of the nucleus, which is known as messenger RNA.

这种带有五端帽和三端帽poly-A尾巴的RNA被称为一种特殊类型的RNA，称为信使RNA。为什么叫信使？因为它正在从细胞核向细胞质发出有关下一步需要发生的信息。换句话说，它具有整个细胞的宏伟蓝图，这就是我要构建的细胞这一部分的计划，这是来自细胞核中心部分的信息。被称为信使RNA。

So this messenger RNA now has a bunch of nucleotides. Of course, now it’s using slightly different letters. It’s using the A; it’s using the C; it’s using the G. But instead of a T, it’s using a U, and it’s single-stranded. When I say it’s single-stranded, it’s single-stranded because it is ready to be translated. In other words, we’re now going to switch into a different language. Instead of nucleotide-base pairs, we’re going to be switching into the language of proteins. Proteins, if you don’t know, are made up of amino acids, and so we’re going to be going from the language of nucleotides to the language of Holly peptides, or proteins, or amino acids. That’s known as not transcription, but rather translation, because it’s a different language.

因此，该信使RNA现在具有一堆核苷酸。当然，现在使用的字母略有不同。它使用A；它使用C;它使用G。但是不是T，而是使用U，并且它是单链的。当我说它是单链的时，它是单链的，因为它已准备好进行翻译。换句话说，我们现在要切换到另一种语言。代替核苷酸碱基对，我们将切换到蛋白质语言。蛋白质，如果您不知道，是由氨基酸组成的，因此，我们将从核苷酸的语言变为Holly肽，蛋白质或氨基酸的语言。这不是转录，而是翻译，因为它是另一种语言。

And so what happens here is that you get a ribosome. A ribosome sits back on here. There’s a small and a large ribosome and there are some spaces here for another kind of RNA to come along. That’s been made before and that is a tRNA. What’s the purpose of a tRNA? There are many many, many different types of tRNAs. All of which are bound to it to have an amino acid, a different amino acid. There are 20 different amino acids.

因此，这里发生的是您得到了核糖体。核糖体坐在这里。核糖体大小不一，这里还有一些空间可以容纳另一种RNA。那是以前做的，那是tRNA。 tRNA的目的是什么？有很多很多不同类型的tRNA。所有这些都结合有一个氨基酸，一个不同的氨基酸。有20种不同的氨基酸。

So tRNA with its amino acid has three codons, or anticodons, as we’ll call them, base pairs that fit perfectly into that code, and it would fit perfectly in there and bring its amino acid in, and then this whole structure would move down through three nucleotides till it gets to another code, and now this amino acid would be attached to this, and so as it goes down, this messenger RNA, through the process of translation, will convert the language of nucleotides into the language of polypeptides.

因此，带有氨基酸的tRNA具有三个密码子或反密码子，我们将其称为完美匹配该密码的碱基对，它将完全适合该密码子并将其氨基酸引入，然后整个结构将向下移动三个核苷酸直到到达另一个密码，现在该氨基酸将附着在其上，因此当其下降时，该信​​使RNA通过翻译过程会将核苷酸的语言转换为多肽。

Now the end process of that is a long polypeptide with a bunch of amino acids. If you aren’t aware, amino acids have the chemical composition of N-CC; that’s one. Another one NCC; that’s a nitrogen-carbon-carbon, and N-CC. These polypeptides, these proteins, do everything in the cell. These are the proteins that can, for instance, make hemoglobin that binds oxygen. These are the proteins that are going to be involved in cellular respiration like glycolysis.

现在，它的最终过程是带有一束氨基酸的长多肽。如果您不知道，氨基酸具有N-CC的化学成分。那是一个。另一个NCC；那是氮-碳-碳和N-CC。这些多肽，这些蛋白质在细胞中起着所有作用。这些蛋白质可以例如制造结合氧的血红蛋白。这些蛋白质将像糖酵解一样参与细胞呼吸。

So you have a whole bunch of these enzymes and proteins, and there are hundreds of thousands of different proteins. If you want to move your muscle, guess what? That’s an interaction with actin and myosin. Those are all proteins that are made, and they all have a specific shape and size, and it’s very important that those proteins look exactly the same.

因此，您拥有大量的这些酶和蛋白质，并且有成千上万种不同的蛋白质。如果您想移动肌肉，您猜怎么着？那是肌动蛋白和肌球蛋白的相互作用。这些都是蛋白质，它们都有特定的形状和大小，这些蛋白质看起来完全一样非常重要。

If that one amino acid changes, then the whole protein may not work. So this is what happens in sickle cell. Anemia is when you have a glutamic amino acid getting substituted and change to a valine amino acid, and that causes sickle cell anemia.

如果一个氨基酸发生变化，则整个蛋白质可能无法工作。这就是镰状细胞中发生的情况。贫血是指您的谷氨酸被取代并变为缬氨酸，从而导致镰状细胞性贫血。

It is important that these amino acids be coded for correctly. That is what happens with transcription and translation. These proteins can be made in different ways. You can have a ribosome making on a messenger RNA, a protein which just goes into the cytoplasm; or you can have these proteins arrange themselves on cellular structures like the rough endoplasmic reticulum and the Golgi apparatus, in which case these proteins will be embedded in these organelles. When they go and fuse with the cell surface, they will actually put the protein in the cell surface so that if it were to butt off, you would have these proteins embedded in the cell surface.

这些氨基酸必须正确编码，这一点很重要。那就是转录和翻译发生的情况。这些蛋白质可以以不同的方式制备。您可以在信使RNA上制造核糖体，信使RNA是一种进入细胞质的蛋白质。或者，您也可以将这些蛋白质安排在细胞结构上，例如粗糙的内质网和高尔基体，在这种情况下，这些蛋白质将嵌入这些细胞器中。当它们与细胞表面融合时，它们实际上会将蛋白质置于细胞表面，这样，如果将其对接，就会将这些蛋白质嵌入细胞表面。

This is important because viruses will use all of this to make more viruses because viruses have proteins inside of them that have to be made again, and viruses have proteins on their cell surface that have to be made again. So depending on where the virus wants those proteins to be made, then it’s going to basically direct those proteins and ribosomes to either the Golgi apparatus or the rough endoplasmic reticulum, or just to be made in the cytoplasm itself.

这很重要，因为病毒将利用所有这些来制造更多的病毒，因为病毒内部必须重新制造蛋白质，而病毒在细胞表面必须重新制造蛋白质。因此，根据病毒希望在何处制造这些蛋白质而定，它将基本上将这些蛋白质和核糖体引导至高尔基体或粗糙的内质网，或仅在细胞质本身中进行制造。

The reason why I bring all of this up is because what a virus is going to do when it infects a cell is it is actually going to take over the machinery of this cell. So it’s going to take over transcription, potentially. It’s going to be taking over translation. It’s going to be taking over the use of the Golgi apparatus and the rough endoplasmic reticulum. Its purpose is going to take all of these things in your cell, which is to make you have a fuller life. It’s going to do one thing, and that is to make more viruses and different viruses and do it in different ways. So we’re going to talk about that.

我之所以提出所有这些建议，是因为病毒感染细胞时将要采取的行动实际上是接管该细胞的机器制造。因此，它将有可能接管转录。它将会接管翻译。它将会取代高尔基体和粗糙的内质网的使用。它的目的是将所有这些东西带入您的细胞，这将使您过上愚蠢的生活。它只会做一件事，那就是制造更多的病毒和不同的病毒，并以不同的方式来制造。因此，我们将讨论这一点。

Now that you understand a little bit about molecular biology, it’s going to make sense. So, please join us for our update where we talk about the coronavirus and how it invades the cell, and does what it does. We’ll talk about other viruses, and we can compare and contrast. Thanks for joining us.

现在，您对分子生物学有所了解，这将很有意义。因此，请加入我们的更新，在其中我们讨论冠状病毒及其如何侵入细胞以及如何发挥作用。我们将讨论其他病毒，我们可以进行比较和对比。感谢您加入我们。