Na+ binding to meizothrombin desF1

Meizothrombin is the physiologically active intermediate generated by a single cleavage of prothrombin at R320 to separate the A and B chains. Recent evidence has suggested that meizothrombin, like thrombin, is a Na(+)-activated enzyme. In this study we present the first X-ray crystal structure of human meizothrombin desF1 solved in the presence of the active site inhibitor PPACK at 2.1 A resolution. The structure reveals a Na(+) binding site whose architecture is practically identical to that of human thrombin. Stopped-flow measurements of Na(+) binding to meizothrombin desF1 document a slow phase of fluorescence change with a k(obs) decreasing hyperbolically with increasing [Na(+)], consistent with the existence of three conformations in equilibrium, E*, E and E:Na(+), as for human thrombin. Evidence that meizothrombin exists in multiple conformations provides valuable new information for studies of the mechanism of prothrombin activation.     

添加剂对AN多变晶型影响研究

本文运用热分析的方法对四十余种无机、有机添加剂和几种表面活性剂及水分对硝酸铵(AN)晶型转变的影响进行了研究。结果表明这些添加剂对AN的影响应为多种因素的综合结果。     

Tribbles: novel regulators of cell function; evolutionary aspects

Identification of rate-limiting steps or components of intracellular second messenger systems holds promise to effectively interfere with these pathways under pathological conditions. The emerging literature on a recently identified family of signalling regulator proteins, called tribbles gives interesting clues for how these proteins seem to link several ‘independent’ signal processing systems together. Via their unique way of action, tribbles co-ordinate the activation and suppression of the various interacting signalling pathways and therefore appear to be key in determining cell fate while responding to environmental challenges. This review summarises our current understanding of tribbles function and also provides an evolutionary perspective on the various tribbles genes. Received 10 January 2006; received after revision 20 March 2006; accepted 5 April 2006     

图书馆的人力资源建设

分析了人才资源与图书馆生存和发展的关系,指出：应从发现人才、重用人才和培养人才3个方面建立人才培养机制;同时强调只有加强领导班子建设才能充分发挥人才的作用。