The CCR5 chemokine receptor acts as a co-receptor for HIV-1 viral entry. Here we report the 2.7 Å resolution crystal structure of human CCR5 bound to the marketed HIV drug Maraviroc. The structure reveals a ligand binding site that is distinct from the proposed major recognition sites for chemokines and the viral glycoprotein gp120, providing insights into the mechanism of allosteric inhibition of chemokine signaling and viral entry. A comparison between CCR5 and CXCR4 crystal structures, along with models of co-receptor/gp120-V3 complexes, suggests that different charge distributions and steric hindrances caused by residue substitutions may be major determinants of HIV-1 co-receptor selectivity. These high-resolution insights into CCR5 can enable structure-based drug discovery for the treatment of HIV-1 infection.

No abstract

No abstract

UIO-67 MOFs functionalized with a [Ru(dcbpy)(bpy)2]2+ photosensitizer and a Pt(dcbpy)Cl2 catalyst display enhanced photocatalytic activity, due to the facile electron transfer from the Ru- to Pt-centers in the MOFs.

a b s t r a c tChina has undergone a dramatic transition echoed the unprecedented urbanization and economic growth since the late 1970s. The current research on urbanization has overlooked the transformation consistency between urban and rural areas. Although the Chinese central government has focused on improving rural residents' livelihood, it is still far from achieving coordinated urbanerural development. This paper provides a comprehensive assessment of China's urbanerural development transformation (URDT) based on three indicator systems, namely the urbanerural development level (URDL), the urban erural structure level (URSL), and the urbanerural coordination level (URCL). Findings from this investigation show that universal and intense URDT has taken place in China over the last two decades. This has been accompanied by growth of URDL and URSL and deterioration of URCL. There are, however, obvious spatial disparities in the different aspects of URDT. The western and northeastern regions of China have experienced slower transformation than other regions between 1990 and 2010. Correlation analysis among the sub-index shows that coordinated urbanerural development needs a certain initial socioeconomic level and moderate changes of URDL and URSL. This paper suggests that more attentions should be paid to rural areas and lagging areas in central and western China. Given the regional disparities of URDT, the most effective way to achieve urbanerural integration in China is by taking the overall considerations of development policies of both region and urbanerural areas aimed at various urbanerural development transformation characteristics.

Rice paddy is a major source of anthropogenic terrestrial methane (CH 4 ). China has the second-largest area of rice cultivation in the world, accounting for ca. 19% of the world's rice-producing area. Recognizing the significance of China's rice cultivation in the global CH 4 budget, we estimated the CH 4 emissions resulting from irrigated rice cultivation in China from 1960 to 2050 using a CH4MOD model. The model estimates suggest that the annual CH 4 emissions decreased from 5.62 Tg yr À1 in 1960 to 4.13 Tg yr À1 in 1970, and this decrease was attributed to changes in water management from continuous flooding to mid-season drainage irrigation. Since the early 1970s, the amount of CH 4 emissions gradually increased to 6.85 Tg yr À1 by 2009 because of significant improvements in crop production that led to high-crop residue retention. Higher levels of CH 4 emissions occurred in southern China, where double rice cropping systems are most common. For the A1B and B1 scenarios of the IPCC Special Report on Emissions Scenarios (SRES), the amount of CH 4 emissions from 2010 to 2050 is predicted to increase at an average rate of 1.2 kg ha À1 yr À1 in response to global warming. Compared to 2009, the CH 4 flux is predicted to increase by ca. 14% by the late 2040s, and the increase in these emissions in northeastern China is estimated to become more significant than in the other rice-growing regions of the country. Under the assumptions that the rice-producing land area will remain the same, decrease by 25% or increase by 38% by the late 2040s, the CH 4 emissions are projected to be 7.8, 5.6 or 11.7 Tg yr À1 , respectively.

No abstract

No abstract