Calculating Ensemble Averaged Descriptions of Protein Rigidity without Sampling

Previous works have demonstrated that protein rigidity is related to thermodynamic stability, especially under conditions that favor formation of native structure. Mechanical network rigidity properties of a single conformation are efficiently calculated using the integer body-bar Pebble Game (PG) algorithm. However, thermodynamic properties require averaging over many samples from the ensemble of accessible conformations to accurately account for fluctuations in network topology. We have developed a mean field Virtual Pebble Game (VPG) that represents the ensemble of networks by a single effective network. That is, all possible number of distance constraints (or bars) that can form between a pair of rigid bodies is replaced by the average number. The resulting effective network is viewed as having weighted edges, where the weight of an edge quantifies its capacity to absorb degrees of freedom. The VPG is interpreted as a flow problem on this effective network, which eliminates the need to sample. Across a nonredundant dataset of 272 protein structures, we apply the VPG to proteins for the first time. Our results show numerically and visually that the rigidity characterizations of the VPG accurately reflect the ensemble averaged properties. This result positions the VPG as an efficient alternative to understand the mechanical role that chemical interactions play in maintaining protein stability

Updated list of bat species positive for rabies in Brazil Lista atualizada das espécies de morcegos positivas para raiva no Brasil

This paper presents an updated list of bat species positive for rabies in Brazil. It was developed based on database research via the internet, of international and national literature and annals of the most important technical and scientific meetings related to rabies and chiroptera in Brazil from 1996 to 2009. The new list of rabies positive bats consists of 41 species, belonging to 25 genera and three families: Phyllostomidae 43.9%, Vespertilionidae 29.3% and Molossidae 26.8%. In addition, questions were raised regarding the lack of data, including sex, age, circumstances and location of bat capture and incomplete and outdated species identification. Results of genetic and antigenic studies performed on Brazilian rabies positive bats were shown.<br>Esse artigo apresenta uma lista atualizada de espécies positivas para raiva no Brasil e foi desenvolvida a partir da base de dados na internet da literatura nacional, internacional e dos anais das mais importantes reuniões técnicas e científicas, envolvendo raiva e morcegos no Brasil durante o período de 1996 a 2009. A nova lista de morcegos positivos para raiva consiste de 41 espécies, pertencentes a 25 gêneros e três famílias: Phyllostomidae 43.9%, Vespertilionidae 29.3% e Molossidae 26.8%. Também foram discutidas questões como a falta de dados sobre sexo, faixa etária e circunstâncias de captura dos animais e identificação incompleta ou desatualizada das espécies. Resultados dos estudos genéticos e antigênicos realizados em amostras de morcegos brasileiros positivos para raiva foram apresentados