Study on the trans-membrane transporting of different types of ECF transport proteins.

ABC transport protein relies on the energy generated by the breakdown of ATP to drive transcellular membrane transport of signal molecules, nutrients, drug molecules, etc., and is the largest primary active transport protein family in organisms.
ECF transport protein is a new type of ABC intro-transport protein found in recent years, structured by the membrane substrate-specific binding protein EcfS and a trans-membrane protein EcfT and two in-cell ATP binding protein composed of energy coupling module (or ECF module), divided into energy coupling module-specific (Group-I) and shared (Group-II) two categories (Figure 1a).
ecfS protein for each ecfS protein using a single ECF module, the shared type of several different EcfS protein sharing the same ECF module.
ECF transport proteins are present conservatively in bacteria and plants, mediated by trans-membrane transport of trace nutrients.
in the preliminary work, Zhang Peng's research team analyzed the structure of several shared ECF transport protein complexes and explained the molecular mechanisms of substrate recognition, module sharing and transfilm transport.
, however, there is a lack of understanding of the structure and structure of specialized ECF transport proteins.
researchers from the Institute of Plant Physiology and Ecology of the Shanghai Institute of Life Sciences of the Chinese Academy of Sciences selected CbiMNQO, a typical representative of the specialized ECF transport protein, to carry out structural and physiological research on the subjects.
CbiMNQO is a five-sub-base complex consisting of the membrane protein CbiM, CbiN, CbiQ, and the ATP binding protein CbiO in the cytokine (Figure 1a).
researchers established a mass spectrometrometrometrometrometrometration activity detection system and found that CbiMNQO's Co2 plus transport activity requires N proteins (Figure 1b).
in vitro, N protein has no effect on the ATP hydrolytic activity of the complex, while CbiM protein has a strong activation effect on the hydrolytic activity of the complex ATP, and activation does not depend on the presence of substrate Co2 plus (Figure 1c).
analyzed the crystal structure of the CbiMQO complex's 2.8-degree resolution (Figure 1d).
by comparing the CbiM of the substrate release state of the CbiMQO complex with the NikM of the previously reported substrate binding state, it is found that the L1 loop connecting the 2nd and 3rd transmeral spirals has undergone significant compositional changes (Figure 1e), which can be used as a gate switch for the substrate to enter and exit CbiM.
Further, by analyzing the structure of the CbiO protein in the ATP binding state (off the composition) in the compound, and comparing it with the CbiO structure (open composition) in the ATP release state in the CbiMQO complex structure, it is revealed that the compositional changes of the CbiO protein in the transport complex in the ATP binding and release process (Figure 1f).
Given that the lack of CbiN does not affect the ATP hydrolytic vitality of the complex, but the experimental results of the loss of Co2 plus transport activity, the researchers predict that the CbiN protein plays an important role in the configuration coupling between CbiM and CbiQ (Figure 1g).
this is the first report on the structure of the specialized ECF transport protein complex, and it is of great significance to understand the transfilm transporting process of different types of ECF transport protein.
The findings were published online March 21 in Cell Research, with Bao Zhihao and Qi Xiaofeng, Ph.D. students in the Zhang Peng Research Group of the Institute of Plant Ecology of the Shanghai Academy of Sciences of the Chinese Academy of Sciences, as co-authors of the paper, researcher Zhang Peng and Tsinghua University professor Wang Jiawei as co-authors of the paper.
research work has been greatly helped by li Model Research Group, a researcher at the Institute of Plant Ecology of the Shanghai Academy of Health Sciences, and Li Model Research Group, a researcher at the Institute of Biochemistry and Cell Biology.
crystal diffraction data collection has been supported by the National Protein Center 19U1/18U1 line station and Shanghai light source 17U line station.
the project was funded by the Ministry of Science and Technology, the Fund Committee and the Chinese Academy of Sciences.
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