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Chinese researchers use bacteria to remove toxic chemicals from water.

China to lift nationality restrictions on top science awards.

Why sunshine improves mood and makes us smarter.

Science fund to support innovation.

Human embryonic stem cell-derived neurons for treating Parkinson’s disease.

DNA analysis reveals distinct lineage of ancient panda in South China.

Cryo-EM reveals interaction between major drug targets.

Fetal imaging equipment improved.

Chinese, French scientists develop one-two punch for cancer treatment.

Tech giants tap into AI healthcare market.

Chinese ‘nurse sharing’ app to offer at-home care.

Esco invests RMB100 million into Innovation Center in China.

Nutrition Society of China and Russia jointly promote dairy industry development.

Merck’s collaborations in China: Alibaba Health and Tongji University.

Water is the most abundant molecule in cells on the earth. The cell membranes are therefore required to provide an effective water channel function. By electron crystallography using electron cryo-microscopy, with a super cooled stage, the structure of the water channel protein; aquaporin-1 is analyzed. The resolved structure reveals a unique folding structure allowing an intriguing mechanism for water channeling. This exemplifies how improvement in technical design, based on theoretical considerations, has successfully advanced scientific insight.

Cryo-electron microscopy provides the means to quantitatively study macromolecules in their native state. However, the original mass distribution of the macromolecule is distorted by the contrast transfer function (CTF) of the electron microscope. In addition, the zeros of the CTF put a practical limit on the resolution that can be achieved. Substantial improvement to the quality of the results can be accomplished by collecting the data using a series of defocus settings. Such data sets can be combined and the resolution can be extended beyond the first zero of the CTF. This procedure can be applied either at the stage of raw data, or more effectively at the stage of reconstructed volumes which have a high signal-to-noise ratio as a result of averaging over many projections. A method of three-dimensional (3D) reconstruction that combines an algebraic, iterative 3D reconstruction technique with CTF correction is proposed. The potential to incorporate a priori knowledge into the reconstruction process is discussed. This approach was used to obtain a 3D reconstruction of the E. coli 70S ribosome from energy-filtered cryo-images.

A Brownian machine, a tiny device buffeted by the random motions of molecules in the environment, is capable of exploiting these thermal motions for many of the conformational changes in its work cycle. Such machines are now thought to be ubiquitous, with the ribosome, a molecular machine responsible for protein synthesis, increasingly regarded as prototypical. Here we present a new analytical approach capable of determining the free-energy landscape and the continuous trajectories of molecular machines from a large number of snapshots obtained by cryogenic electron microscopy. We demonstrate this approach in the context of experimental cryogenic electron microscope images of a large ensemble of nontranslating ribosomes purified from yeast cells. The free-energy landscape is seen to contain a closed path of low energy, along which the ribosome exhibits conformational changes known to be associated with the elongation cycle. Our approach allows model-free quantitative analysis of the degrees of freedom and the energy landscape underlying continuous conformational changes in nanomachines, including those important for biological function.