Heptosyltransferase I (HepI), the enzyme responsible for the transfer of L-glycero-D-manno-heptose to a 3-deoxy-α-D-oct-2-ulopyranosonic acid (Kdo) of the growing core region of lipopolysaccharide (LPS), is a member of the GT-B structural class of enzymes. Crystal structures have revealed open and closed conformations of apo and ligand-bound GT-B enzymes, implying that large-scale protein conformational dynamics play a role in their reaction mechanism. Here we report transient kinetic analysis of conformational changes in HepI reported by intrinsic tryptophan fluorescence, and present the first real time evidence for a GT-B enzyme undergoing substrate binding-induced transition from an open to closed state prior to catalysis.

Purpose:To show the effect of holistic Ayurvedic Treatment in a critical disease like psoriasis in early stage.Method:A patient of known case of psoriasis (not more than 2 yrs) given systematic Ayurvedic Shodhana Karma every 3 yrs.Result:After shodhana Karma, patient got both Subjective & objective relief from Symptoms for a long duration than modern medicines.Conclusion:Pure Ayurvedic Traditional treatment can give relief from symptoms of psoriasis for a longer time without any side effect.

G-Protein Coupled Receptors (GPCRs) are structurally flexible membrane proteins(1), that mediate a host of physiological responses to extracellular ligands like hormones and neurotransmitters(2). Details of the dynamic structural behavior are hypothesized to encode functional plasticity seen in GPCR activity(1), where ligands with different efficacies can direct the same receptor towards different signaling phenotypes. Although the number of GPCR crystal structures is increasing(3-5), the receptors are characterized by complex and poorly understood conformational landscapes(6). Therefore, we have developed a fluorescence microscopy assay to study the activation and dynamics of single b2-Adrenergic Receptors (b2ARs) reconstituted in liposomes. Conformational fluctuations are monitored by changes in intensity of a small fluorescent molecule conjugated to an endogenous cysteine located at the cytoplasmic end of the sixth trans-membrane helix of the receptor. By imaging arrays of surface-tethered proteoliposomes, we can read out the dynamic properties of hundreds of single b2AR reconstituted in a lipid membrane. Our data reveal subtle changes in b2AR conformational dynamics with agonist stimulation, which would be undetectable in bulk assays(7-9). References: 1.

Mismatch repair mechanisms improve DNA replication fidelity to only one base‐pairing error in 109 nucleotides. Msh2‐Msh6 (MutSα) is responsible for initiating repair of single base mismatches and small insertion/deletion loops and Msh2‐Msh3 (MutSβ) is responsible for insertion/deletion loops. However, Msh2‐Msh3 can also stabilize loops/hairpins formed by repeat nucleotide sequences and contribute to triplet nucleotide repeat (TNR) expansion. The goal of this study is to investigate the S.cerevisiae Msh2‐Msh3 mechanism of action by transient kinetics, in order to understand how it can accomplish both loop repair and expansion. Thus far, yMsh2‐Msh3 protein complex has been expressed in E.coli host cells and can be purified in large quantity for biochemical studies. I am optimizing the purification protocol by testing different ion exchange and affinity exchange chromatography resins. I am also developing different DNA substrates to assay the affinity and kinetics of yMsh2‐Msh3 binding to loops/hairpins and its coupled ATPase activity. This study is expected to yield kinetic parameters that distinguish between yMsh2‐Msh3 actions that trigger loop repair versus TNR expansion.

List of figures (I) VI. a. ii. The Hep I reaction mechanism 75 VI. a. iii. Emission spectra of Hep I with OLDA 76 VI. a. iv. Structure of Hep I depicting tryptophan's 76 VI. a. v. Stopped flow traces of Hep I and substrate 77 VI. a. vi. Titration of Hep I versus ODLA 77 VI. a. vii. Kinetics of ODLA binding and associated change in Hep I conformation 78 VI. a. viii. Scheme of two-step binding of ODLA to Hep I 79 VI. b. i. Experimental setup of the experiment to determine the ADP release rate of Hep I.