Extracellular vesicles: Taking metabolism on the road

August 18th, 2017 by Lucas B Sullivan

Nature Chemical Biology 13, 924 (2017). doi:10.1038/nchembio.2455

Author: Lucas B Sullivan

Extracellular vesicles (EVs) are a class of secreted membrane particles capable of transferring biological molecules between cells. Metabolomics measurements indicate that isolated EVs also have autonomous metabolic enzyme activities, including the unexpected identification of endogenous human asparaginase activity.

Protein design: I like to fold it, fold it

August 18th, 2017 by Caitlin Deane

Nature Chemical Biology 13, 923 (2017). doi:10.1038/nchembio.2467

Author: Caitlin Deane

Neurobiology: Lighting up neurons

August 18th, 2017 by Grant Miura

Nature Chemical Biology 13, 923 (2017). doi:10.1038/nchembio.2469

Author: Grant Miura

Bacterial immunity: A virtuous CRISPR cycle

August 18th, 2017 by Terry L. Sheppard

Nature Chemical Biology 13, 923 (2017). doi:10.1038/nchembio.2468

Author: Terry L. Sheppard

Drug development: Locking down metabolism

August 18th, 2017 by William R Bishai

Nature Chemical Biology 13, 925 (2017). doi:10.1038/nchembio.2452

Author: William R Bishai

An allosteric inhibitor of Mycobacterium tuberculosis tryptophan synthase—an enzyme that is nonessential for in vitro growth—has potent antimicrobial activity, revealing a potentially expanded target list for antimicrobials and greater chemical space for new inhibitors.

A kinetic view of GPCR allostery and biased agonism

August 18th, 2017 by J Robert Lane

Nature Chemical Biology 13, 929 (2017). doi:10.1038/nchembio.2431

Authors: J Robert Lane, Lauren T May, Robert G Parton, Patrick M Sexton & Arthur Christopoulos

Ubiquitin-proteasome system: Rescuing EBV latency

August 18th, 2017 by Mirella Bucci

Nature Chemical Biology 13, 923 (2017). doi:10.1038/nchembio.2466

Author: Mirella Bucci

Lysine Deacetylases Exhibit Distinct Changes in Activity Profiles Due to Fluorophore Conjugation of Substrates

August 16th, 2017 by Tasha B. Toro, Jenae R. Bryant and Terry J. Watt

TOC Graphic

DOI: 10.1021/acs.biochem.7b00270

Functional Complementation Studies Reveal Different Interaction Partners of Escherichia coli IscS and Human NFS1

August 16th, 2017 by Martin Bühning, Martin Friemel and Silke Leimkühler

TOC Graphic

DOI: 10.1021/acs.biochem.7b00627

Structural analyses of the bacterial primosomal protein DnaB reveal that it is a tetramer and forms a complex with a primosomal re-initiation protein [Protein Structure and Folding]

August 14th, 2017 by Yi-Ching Li, Vankadari Naveen, Min-Guan Lin, Chwan-Deng Hsiao

The DnaB primosomal protein from Gram-positive bacteria plays a key role in DNA replication and restart as a loader protein for the recruitment of replisome cascade proteins. Previous investigations have established that DnaB is composed of an N-terminal domain, a middle domain, and a C-terminal domain. However, structural evidence for how DnaB functions at the atomic level is lacking. Here, we report the crystal structure of DnaB, encompassing the N-terminal and middle domains (residues 1-300), from Geobacillus stearothermophilus (GstDnaB1-300) at 2.8 Å resolution. Our structure revealed that GstDnaB1-300 forms a tetramer with two basket-like architecture, a finding s consistent with those from solution studies using analytical ultracentrifugation. Furthermore, our results from both GST pull-down assays and analytical ultracentrifugation show that GstDnaB1-300 is sufficient to form a complex with PriA, the primosomal re-initiation protein. Moreover, with the aid of small angle X-ray scattering (SAXS) experiments, we also determined the structural envelope of full-length DnaB (GstDnaBFL) in solution. These SAXS studies indicated that GstDnaBFL has an elongated conformation and that the protruding density envelopes originating from GstDnaB1-300 could completely accommodate the GstDnaB C-terminal domain (residues 301-461) . Taken together with biochemical assays, our results suggest that GstDnaB uses different domains to distinguish the PriA-interaction and ssDNA-binding. This finding can further extend our understanding of primosomal assembly in replication restart.
  • Posted in Journal of Biological Chemistry, Publications
  • Comments Off on Structural analyses of the bacterial primosomal protein DnaB reveal that it is a tetramer and forms a complex with a primosomal re-initiation protein [Protein Structure and Folding]