Co-adaption of tRNA gene copy number and amino acid usage influences translation rates in three life domains.

Although more and more entangled participants of translation process were realized, how they cooperate and co-determine the final translation efficiency still lacks details. Here, we reasoned that the basic translation components, tRNAs and amino acids should be consistent to maximize the efficiency and minimize the cost. We firstly revealed that 310 out of 410 investigated genomes of three domains had significant co-adaptions between the tRNA gene copy numbers and amino acid compositions, indicating that maximum efficiency constitutes ubiquitous selection pressure on protein translation. Furthermore, fast-growing and larger bacteria are found to have significantly better co-adaption and confirmed the effect of this pressure. Within organism, highly expressed proteins and those connected to acute responses have higher co-adaption intensity. Thus, the better co-adaption probably speeds up the growing of cells through accelerating the translation of special proteins. Experimentally, manipulating the tRNA gene copy number to optimize co-adaption between enhanced green fluorescent protein (EGFP) and tRNA gene set of Escherichia coli indeed lifted the translation rate (speed). Finally, as a newly confirmed translation rate regulating mechanism, the co-adaption reflecting translation rate not only deepens our understanding on translation process but also provides an easy and practicable method to improve protein translation rates and productivity.

Predicting subcellular localization of mycobacterial proteins by using Chou's pseudo amino acid composition.

The successful prediction of protein subcellular localization directly from protein primary sequence is useful to protein function prediction and drug discovery. In this paper, by using the concept of pseudo amino acid composition (PseAAC), the mycobacterial proteins are studied and predicted by support vector machine (SVM) and increment of diversity combined with modified Mahalanobis Discriminant (IDQD). The results of jackknife cross-validation for 450 non-redundant proteins show that the overall predicted successful rates of SVM and IDQD are 82.2% and 79.1%, respectively. Compared with other existing methods, SVM combined with PseAAC display higher accuracies.

A novel mutation in EXT2 gene in a Chinese family with hereditary multiple exostoses.

Hereditary multiple exostoses (HME) is an autosomal-dominant disorder characterized by the presence of bony outgrowths on the long bones. In this report, we describe a Chinese family with HME. Linkage analysis and mutation detection were performed. Linkage with the EXT2 was established in this family. A novel mutation, EXT2 c239-244delG, was identified. Mutation analysis in a family with HME allows for genetic counseling and prenatal diagnosis.

[Temperature dependence study of calf thymus DNA by Raman spectra].

In this paper, the authors obtained Raman spectra of DNA in fiber and aqueous solution at different temperatures. These spectra revealed that the vibration of bases and phosphate group were influenced by varying temperature. Adenine was the most sensitive to varying temperature in all of the vibrational modes. The wave numbers of most of the vibrational modes decreased as the temperature increased except for the band at 1101 cm(-1), and the shift of wave numbers mainly concentrated upon the beginning point of denaturation at 70 degrees C. The temperature dependence of Raman intensity was discussed, and two peaks were obtained at 38 and 82 degrees C, respectively. The results obtained by Raman spectra were in agreement with experimental data by DSC at 82 degrees C. The peak at 38 degrees C was related to the biological activity region of DNA function.