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Gating of ion channels is strictly regulated by physiological conditions as well as intra/extracellular ligands. To understand the underlying structures mediating ion channel gating, we investigated the pH-dependent gating of the K(+) channel KcsA under near-physiological conditions, using solution-state NMR. In a series of (1)H(15)N-TROSY HSQC (transverse(More)
—Non-negative Tensor Factorization (NTF) is a widely used technique for decomposing a non-negative value tensor into sparse and reasonably interpretable factors. However, NTF performs poorly when the tensor is extremely sparse, which is often the case with real-world data and higher-order tensors. In this paper, we propose Non-negative Multiple Tensor(More)
Non-negative Matrix Factorization (NMF) is a traditional unsupervised machine learning technique for decomposing a matrix into a set of bases and coefficients under the non-negative constraint. NMF with sparse constraints is also known for extracting reasonable components from noisy data. However, NMF tends to give undesired results in the case of highly(More)
The human Mediator coactivator complex interacts with many transcriptional activators and facilitates recruitment of RNA polymerase II to promote target gene transcription. The MED25 subunit is a critical target of the potent herpes simplex 1 viral transcriptional activator VP16. Here we determine the solution structure of the MED25 VP16-binding domain(More)
—The amount and variety of multimedia data such as images, movies and music available on over social networks are increasing rapidly. However, the ability to analyze and exploit these unorganized multimedia data remains inadequate, even with state-of-the-art media processing techniques. Our finding in this paper is that the emerging social curation service(More)
The action mechanism of sapecin, an antibacterial peptide with membrane permeabilization activity, was investigated. The dose dependence of the membrane permeabilization caused by sapecin was sigmoidal, suggesting that sapecin oligomerization leads to the membrane permeabilization. Solution nuclear magnetic resonance analysis of the sapecin-phospholipid(More)
LmrR is a multidrug transcriptional repressor that controls the expression of a major multidrug transporter, LmrCD, in Lactococcus lactis. However, the molecular mechanism by which LmrR binds to structurally unrelated compounds and is released from the promoter region remains largely unknown. Here, we structurally and dynamically characterized LmrR in the(More)
omega-Grammotoxin SIA (GrTx) is a 36 amino acid residue protein toxin from spider venom that inhibits P/Q and N-type voltage-gated Ca(2+) channels by modifying voltage-dependent gating. We determined the three-dimensional structure of GrTx using NMR spectroscopy. The toxin adopts an "inhibitor cystine knot" motif composed of two beta-strands (Leu19-Cys21(More)
We have determined the binding site on agitoxin2 (AgTx2) to the KcsA K(+) channel by a transferred cross-saturation (TCS) experiment. The residues significantly affected in the TCS experiments formed a contiguous surface on AgTx2, and substitutions of the surface residues decreased the binding affinity to the KcsA K(+) channel. Based on properties of the(More)