RESUMO
Lysine acetylation is a reversible and highly regulated post-translational modification that plays a critical role in regulating many aspects of cellular processes, both in bacteria and in eukaryotes. However, this modification has not been systematically studied in archaea. Herein, we report the lysine acetylome of a model haloarchaeon, Haloferax mediterranei. Using immunoaffinity enrichment and LC-MS/MS analysis, we identified 1017 acetylation sites in 643 proteins, accounting for 17.3% of the total proteins in this haloarchaeon. Bioinformatics analysis indicated that lysine acetylation mainly distributes in cytoplasm (94%) and participates in protein biosynthesis and carbon metabolism. Specifically, the acetylation of key enzymes in PHBV biosynthesis further suggested that acetylation plays a key role in the energy and carbon storage. In addition, a survey of the acetylome revealed a universal rule in acetylated motifs: a positively charged residue (K, R, or H) located downstream of acetylated lysine at the positions +1, +2, or +3. Interestingly, we identified acetylation in several replication initiation proteins Cdc6; mutation on the acetylated site of Cdc6A destroyed the Autonomous Replication Sequence (ARS) activity of its adjacent origin oriC1. Our study indicates that lysine acetylation is an abundant modification in H. mediterranei, and plays key roles in the processes of replication, protein biosynthesis, central metabolism, and carbon storage. This acetylome of H. mediterranei provides opportunities to explore the physiological role of acetylation in halophilic archaea.
Assuntos
Proteínas Arqueais/metabolismo , Proteínas de Ciclo Celular/metabolismo , DNA Arqueal/metabolismo , Haloferax mediterranei/metabolismo , Lisina/metabolismo , Processamento de Proteína Pós-Traducional , Acetilação , Sequência de Aminoácidos , Proteínas Arqueais/genética , Proteínas de Ciclo Celular/genética , Biologia Computacional/métodos , Replicação do DNA , DNA Arqueal/genética , Metabolismo Energético/genética , Ontologia Genética , Haloferax mediterranei/genética , Anotação de Sequência Molecular , Biossíntese de Proteínas , Alinhamento de Sequência , Homologia de Sequência de AminoácidosRESUMO
OBJECTIVE: To investigate the impact of cement distribution index on the occurrence of refracture in the adjacent segments after percutaneous vertebroplasty. METHODS: This retrospective analysis was conducted among 143 patients who received percutaneous vertebroplasty for osteoporotic vertebral compression fracture between April, 2011 and April, 2014. Of the 134 patients with complete follow-up data, 18 had adjacent segment fracture within 1 year following the surgeries (re-fracture group), and 116 patients without new fracture served as the control group. All the patients underwent X-ray examinations after the surgery and according to the position and shape, the cement in the vertebrae were classified into 5 types (I to V), and the volume-cubage index was computed based on the cement volume and vertebral cubage. Age, gender, bone mineral density (BMD), cement distribution index, volume-cubage index, and cement leakage were evaluated in the 2 groups, and the variables with significant differences between the 2 groups were analyzed in Logistic regression analysis. RESULTS: BMD was significantly lower and the rate of cement leakage was significantly higher in the re-fracture group than in the control group (P<0.05). Significant difference was found in cement distribution index between the 2 groups (P<0.05) but not in age, gender, cement volume or volume-cubage index (P>0.05). Logistic regression analysis indicated that BMD, cement leakage and cement distribution index all significantly affected the occurrence of adjacent vertebral fractures following percutaneous vertebroplasty. CONCLUSION: A low BMD, cement leakage and a low cement distribution index are all risks factor of adjacent vertebral fracture after percutaneous vertebroplasty.