米田君、science Vol336, 6089 and 6093
#6089_p1713, CTD tyrosine phosphorylation impairs termination factor recruitment to RNA polymeraseII
RNA polymerase (Pol) II recruits various factors via its C-terminal domain (CTD), which consists of conserved heptapeptide repeats with the sequence Tyr-Ser-Pro-Thr-Ser-Pro-Ser. In this paper, the authors showed that the phosphorylation of Tyrosine affected the recriuitment of termination factor. However, results indicated that this phosphorylation only affect both Pcf11 and Rtt103 factors, but do not give any inhibition to another factor, Nrd1. In my opinion, this kind of inhibition to the recruitment of termination factor by phosphorylation at Tyr site is dependent on category of factors.
本間さん、PNAS Vol. 109, No. 44, 45, 46
Structural insights into the mechanisms of Mg2+ uptake, transport, and gating by CorA. PNAS 2012 109 (45) 18459-18464
They present a 3.2 resolution structure of the archaeal CorA from Methanocaldococcus jannaschii, and this crystal structure reveals the organization of the selectivity filter. They found that polar residues facing the channel coordinate a partially hydrated Mg2+ during the transport. Finally, they proposed a unique gating mechanism involving a helical turn upon the binding of Mg2+ to the regulatory intracellular binding sites, and thus converting a polar ion passage into a narrow hydrophobic pore.
Localized cell death focuses mechanical forces during 3D patterning in a biofilm. PNAS 2012 109 (46) 18891-18896
Although biofilm has been widely researched, a different entering point probably allow us generate some new finding. This paper is a good example to interpret above argument. They proposed one question about the change of mechanical force during cellular process. They described the changes of mechanical forces by investigating wrinkled biofilms of Bacillus subtilis, together with some mathematical modeling. The wrinkled biofilm formed is attributed to a kind of vertical mechanical buckling due to many cells dead in the center, and generating lateral compressive forces.