Scientists "see" the structure of potassium-chlorine co-transport proteins

, sodium, chlorine plasma stable state in human cells once unbalanced, it will lead to high blood pressure, depression, epilepsy and a series of diseases. On the cell membrane, there is a class of proteins called cation-chloride cotranser transport proteins, which can effectively regulate the ion stabilization in cells. Guo Jiangtao of Zhejiang University School of Medicine recently analyzed the high-resolution cryomirscopic structure of 2.9 E of one of these proteins, the human potassium-chlorine cotranser transport protein KCC1, revealed the binding points of potassium and chloride ions, and proposed a model of potassium-chlorine cotransering thermoly transporting. The results were published in Science on October 25.
because KCC2, a member of the potassium-chlorine cotranser transport protein, constantly transfers potassium and chloride ions from within the cell to the outside of the cell, the inhibitory neuron cells are able to maintain a low concentration of chlorine ions. If KCC2 mutates, inhibitory nerve transfer is disrupted, triggering a variety of neurological diseases. But why hasn't the KCC family's veil been lifted? Guo Jiangtao introduced that the reason is that the sample of potassium-chlorine cotranser transport protein is not easy to obtain, and the high-resolution structure analysis of membrane proteins with smaller molecular weight is challenging.
group was optimized for a large number of protein expression and purification conditions, resulting in a sufficient number of KCC1 protein samples that could be used for frozen electroscopy data collection. At this point, the 300 kv high-performance frozen electroscope Titan Krios of Zhejiang University's Frozen Mirror Center came in play. In order to reduce the radiation damage of electrons to proteins, protein samples need to be collected in a frozen environment. Before the data was collected, the researchers used liquid ethane to quickly freeze the protein solution sample on a "copper mesh". The electro-mirror data collection process is a bit like making a movie: take 40 photos in 8 seconds in a row to form a "micro-movie".
team finally obtained two sets of 2.9 E high-resolution KCC1 three-dimensional structure. This will help the next step in designing drugs for KCC to help treat diseases such as epilepsy. (Source: Cui Xueqin, China Science Daily)
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