Deciphering the structure, function, and mechanism of lysine acetyltransferase cGNAT2 in cyanobacteria.

Lysine acetylation is a conserved regulatory posttranslational protein modification that is performed by lysine acetyltransferases (KATs). By catalyzing the transfer of acetyl groups to substrate proteins, KATs play critical regulatory roles in all domains of life; however, no KATs have yet been identified in cyanobacteria. Here, we tested all predicted KATs in the cyanobacterium Synechococcus sp. PCC 7002 (Syn7002) and demonstrated that A1596, which we named cyanobacterial Gcn5-related N-acetyltransferase (cGNAT2), can catalyze lysine acetylation in vivo and in vitro. Eight amino acid residues were identified as the key residues in the putative active site of cGNAT2, as indicated by structural simulation and site-directed mutagenesis. The loss of cGNAT2 altered both growth and photosynthetic electron transport in Syn7002. In addition, quantitative analysis of the lysine acetylome identified 548 endogenous substrates of cGNAT2 in Syn7002. We further demonstrated that cGNAT2 can acetylate NAD(P)H dehydrogenase J (NdhJ) in vivo and in vitro, with the inability to acetylate K89 residues, thus decreasing NdhJ activity and affecting both growth and electron transport in Syn7002. In summary, this study identified a KAT in cyanobacteria and revealed that cGNAT2 regulates growth and photosynthesis in Syn7002 through an acetylation-mediated mechanism.

cKMT1 is a New Lysine Methyltransferase That Methylates the Ferredoxin-NADP(+) Oxidoreductase and Regulates Energy Transfer in Cyanobacteria.

Lysine methylation is a conserved and dynamic regulatory posttranslational modification performed by lysine methyltransferases (KMTs). KMTs catalyze the transfer of mono-, di-, or tri-methyl groups to substrate proteins and play a critical regulatory role in all domains of life. To date, only one KMT has been identified in cyanobacteria. Here, we tested all of the predicted KMTs in the cyanobacterium Synechocystis sp. PCC 6803 (Synechocystis), and we biochemically characterized sll1526 that we termed cKMT1 (cyanobacterial lysine methyltransferase 1) and determined that it can catalyze lysine methylation both in vivo and in vitro. Loss of cKMT1 alters photosynthetic electron transfer in Synechocystis. We analyzed cKMT1-regulated methylation sites in Synechocystis using a timsTOF Pro instrument. We identified 305 class I lysine methylation sites within 232 proteins, and of these, 80 methylation sites in 58 proteins were hypomethylated in ΔcKMT1 cells. We further demonstrated that cKMT1 could methylate ferredoxin-NADP(+) oxidoreductase (FNR) and its potential sites of action on FNR were identified. Amino acid residues H118 and Y219 were identified as key residues in the putative active site of cKMT1 as indicated by structure simulation, site-directed mutagenesis, and KMT activity measurement. Using mutations that mimic the unmethylated forms of FNR, we demonstrated that the inability to methylate K139 residues results in a decrease in the redox activity of FNR and affects energy transfer in Synechocystis. Together, our study identified a new KMT in Synechocystis and elucidated a methylation-mediated molecular mechanism catalyzed by cKMT1 for the regulation of energy transfer in cyanobacteria.

Clinicopathologic features of epithelioid sarcoma: report of seventeen cases and review of literature.

Epithelioid sarcoma (ES) is a rare malignant soft tissue tumor, which is characterized by nodular aggregates of epithelioid cells and immunoreactivity of cytokeratin (CK) as well as epithelial membrane antigen (EMA) and often with CD34. It can be divided into proximal and distal subtypes. Classic ES has a microscopic nodular appearance that is composed of large polygonal epithelioid cells combined with central necrosis, and presents as a subcutaneous or deep dermal mass in the distal extremities of young adults. The proximal variant preferentially occurs in proximal limbs and limb girdles and the midline of the trunk, and is composed of more atypical cells with variable rhabdoid morphology. In this study we investigated the clinicopathologic features of 17 patients diagnosed with ES. In addition, we reviewed relevant literature and discussed some diagnostic and differential diagnostic points of this disease.

[The application of CAD/CAM technology on the reconstruction of the thyroid cartilage].

OBJECTIVE: To explore the value of computer-aided design/computeraided manufacturing (CAD/CAM) technology for individual reconstruction of the thyroid cartilage defects. METHOD: Select the 20 New Zealand white rabbits (male or female). Randomly divided into two groups. Group A in the pre-operative CT scan of the throat, three-dimensional reconstruction of the thyroid cartilage imaging, surgical removal of either side of the thyroid cartilage, defect implanted in the use of CAD/CAM technology and mirror technology to produce personalized restorative materials; Group B surgical resection either side of the thyroid cartilage, defect implanted production of non-personalized probably according to the experimental animals unilateral thyroid cartilage repair materials. After surgery by gross observation, electronic laryngoscopy observed experimental animals throat. RESULT: General check and electronic laryngoscopy show: the use of CAD/CAM technology to prepare the individual repair materials throat plays better supporting role than the non personalized materials. CONCLUSION: CAD/CAM technology before surgery designed to provide a personalized solid model to improve the accuracy of the surgery, time saving surgery to reduce surgical complications.

Large-scale production of graphene by microwave synthesis and rapid cooling.

Graphene was prepared via carbonization of microwave synthesized metal phthalocyanine, followed by a rapid cooling process. The morphology and structure of the obtained graphene were controlled by the coolants.