Structural basis of keto acid utilization in nonribosomal depsipeptide synthesis.

Nonribosomal depsipeptides are natural products composed of amino and hydroxy acid residues. The hydroxy acid residues often derive from α-keto acids, reduced by ketoreductase domains in the depsipeptide synthetases. Biochemistry and structures reveal the mechanism of discrimination for α-keto acids and a remarkable architecture: flanking intact adenylation and ketoreductase domains are sequences separated by >1,100 residues that form a split 'pseudoA' domain, structurally important for the depsipeptide module's synthetic cycle.

Structures of GapR reveal a central channel which could accommodate B-DNA.

GapR is a nucleoid-associated protein required for the cell cycle of Caulobacter cresentus. We have determined new crystal structures of GapR to high resolution. As in a recently published structure, a GapR monomer folds into one long N-terminal α helix and two shorter α helices, and assembles into a tetrameric ring with a closed, positively charged, central channel.

Rocaglates as dual-targeting agents for experimental cerebral malaria.

Cerebral malaria (CM) is a severe and rapidly progressing complication of infection by parasites that is associated with high rates of mortality and morbidity. Treatment options are currently few, and intervention with artemisinin (Art) has limited efficacy, a problem that is compounded by the emergence of resistance to Art in parasites. Rocaglates are a class of natural products derived from plants of the genus that have been shown to interfere with eukaryotic initiation factor 4A (eIF4A), ultimately blocking initiation of protein synthesis.

Piecing together nonribosomal peptide synthesis.

Nonribosomal peptide synthetases (NRPSs) produce peptide products with wide-ranging biological activities. NRPSs are macromolecular machines with modular assembly-line logic, a complex catalytic cycle, moving parts and multiple active sites. They are organized into repeating sets of domains, called modules.

X-Ray Crystallography and Electron Microscopy of Cross- and Multi-Module Nonribosomal Peptide Synthetase Proteins Reveal a Flexible Architecture.

Nonribosomal peptide synthetases (NRPS) are macromolecular machines that produce peptides with diverse activities. Structural information exists for domains, didomains, and even modules, but little is known about higher-order organization. We performed a multi-technique study on constructs from the dimodular NRPS DhbF.