Cytomegalovirus (CMV) is distinct among members of the Herpesviridae family for having the largest dsDNA genome (230 kb). Packaging of large dsDNA genome is known to give rise to a highly pressurized viral capsid, but molecular interactions conducive to the formation of CMV capsid resistant to pressurization have not been described. Here, we report a cryo electron microscopy (cryoEM) structure of the murine cytomegalovirus (MCMV) capsid at a 9.1 Å resolution and describe the molecular interactions among the ∼3000 protein molecules in the MCMV capsid at the secondary structure level. Secondary structural elements are resolved to provide landmarks for correlating with results from sequence-based prediction and for structure-based homology modeling. The major capsid protein (MCP) upper domain (MCPud) contains α-helices and β-sheets conserved with those in MCPud of herpes simplex virus type 1 (HSV-1), with the largest differences identified as a "saddle loop" region, located at the tip of MCPud and involved in interaction with the smallest capsid protein (SCP). Interactions among the bacteriophage HK97-like floor domain of MCP, the middle domain of MCP, the hook and clamp domains of the triplex proteins (hoop and clamp domains of TRI-1 and clamp domain of TRI-2) contribute to the formation of a mature capsid. These results offer a framework for understanding how cytomegalovirus uses various secondary structural elements of its capsid proteins to build a robust capsid for packaging its large dsDNA genome inside and for attaching unique functional tegument proteins outside.
Amino Acid Sequence ; Capsid Proteins ; chemistry ; metabolism ; ultrastructure ; Cryoelectron Microscopy ; Models, Molecular ; Molecular Sequence Data ; Muromegalovirus ; chemistry ; ultrastructure ; Protein Binding ; Protein Multimerization ; Protein Structure, Quaternary ; Protein Structure, Tertiary

Reoviridae ; Cryoelectron Microscopy

Objective To investigate epidemic characteristics of a family aggregation COVID-19, and to provide scientific basis for prevention and control of family aggregation epidemic. Methods] Field epidemiological methods were used to investigate the cases and close contacts of a family aggregation COVID-19 in Y County, Chenzhou City, Hunan Province. Descriptive statistical analysis was used on epidemiological data . The 2019-nCoV nucleic acid was detected by real-time fluorescence quantitative RT-PCR. Results It was found that Ms. Deng was infected with COVID-19 and became the infectious source of the family aggregation epidemic , who had lived in Wuhan Hubei Province. Her boyfriend Mr. Cao became a second-generation case of COVID-19..Another two asymptomatic but infected persons were family members living with Ms.Deng . Conclusion COVID-19 easily spreads within families. The awareness of family members' protection, the education of new coronavirus pneumonia prevention and control in key groups should be strengthened to avoid the occurrence and spread of family aggregation epidemic.

Genome packaging is a fundamental process in a viral life cycle and a prime target of antiviral drugs. Herpesviruses use an ATP-driven packaging motor/terminase complex to translocate and cleave concatemeric dsDNA into procapsids but its molecular architecture and mechanism are unknown. We report atomic structures of a herpesvirus hexameric terminase complex in both the apo and ADP•BeF3-bound states. Each subunit of the hexameric ring comprises three components-the ATPase/terminase pUL15 and two regulator/fixer proteins, pUL28 and pUL33-unlike bacteriophage terminases. Distal to the nuclease domains, six ATPase domains form a central channel with conserved basic-patches conducive to DNA binding and trans-acting arginine fingers are essential to ATP hydrolysis and sequential DNA translocation. Rearrangement of the nuclease domains mediated by regulatory domains converts DNA translocation mode to cleavage mode. Our structures favor a sequential revolution model for DNA translocation and suggest mechanisms for concerted domain rearrangements leading to DNA cleavage.

Objective: To investigate the relationship between body mass index (BMI) and all-cause mortality in hypertensive population. Methods: All participants were selected from a prospective cohort study based on a rural population from Henan province, China. Cox proportional hazards regression models were used to estimate the associations of different levels of BMI stratification with all-cause mortality. Restricted cubic spline models were used to detect the dose-response relation. Results: Among the 5 461 hypertensive patients, a total of 31 048.38 person-years follow-up was conducted. The median of follow-up time was 6 years, and 589 deaths occurred during the follow-up period. Compared to normal weight group (18.5 kg/m(2)%CI: 0.37-1.87), 0.81 (95%CI: 0.67-0.97), and 0.72 (95%CI: 0.56-0.91), respectively. The dose-response analysis showed a nonlinear, reverse "S" shaped relationship (non-linearity P<0.001). Conclusion: Overweight or obese might have a protective effect on all-cause mortality in hypertensive population, which supports the "obesity paradox" phenomenon.
Adult ; Asian People/statistics & numerical data* ; Blood Pressure/physiology* ; Body Mass Index ; Cause of Death ; China/epidemiology* ; Humans ; Hypertension/mortality* ; Middle Aged ; Mortality ; Obesity/mortality* ; Overweight ; Prospective Studies ; Risk Factors ; Young Adult