25 research outputs found
Structure of the cystathionine Îł-synthase MetB from Mycobacterium ulcerans
Cystathionine Îł-synthase (CGS) is a transferase that catalyzes the reaction between O
4-succinyl-l-homoserine and l-cysteine to produce l-Âcystathionine and succinate. The crystal structure of CGS from M. ulcerans is presented covalently linked to the cofactor pyridoxal phosphate (PLP). A second structure contains PLP as well as a highly ordered HEPES molecule in the active site acting as a pseudo-ligand. This is the first structure ever reported from the pathogen M. ulcerans
BrabA.11339.a: anomalous diffraction and ligand binding guide towards the elucidation of the function of a âputative ÎČ-lactamase-like proteinâ from Brucella melitensis
The structure of a ÎČ-lactamase-like protein from B. melitensis was solved independently using two data sets with anomalous signal. Anomalous Fourier maps could confirm the identity of two metal ions in the active site. AMP-bound and GMP-bound structures provide hints to the possible function of the protein
Structure of a Nudix hydrolase (MutT) in the Mg2+-Âbound state from Bartonella henselae, the bacterium responsible for cat scratch fever
B. henselae is the etiological agent responsible for cat scratch fever (bartonellosis). The crystal structure of the smaller of the two Nudix hydrolases encoded in the genome of B. henselae, Bh-MutT, was determined to 2.1â
Ă
resolution
The James Webb Space Telescope Mission
Twenty-six years ago a small committee report, building on earlier studies,
expounded a compelling and poetic vision for the future of astronomy, calling
for an infrared-optimized space telescope with an aperture of at least .
With the support of their governments in the US, Europe, and Canada, 20,000
people realized that vision as the James Webb Space Telescope. A
generation of astronomers will celebrate their accomplishments for the life of
the mission, potentially as long as 20 years, and beyond. This report and the
scientific discoveries that follow are extended thank-you notes to the 20,000
team members. The telescope is working perfectly, with much better image
quality than expected. In this and accompanying papers, we give a brief
history, describe the observatory, outline its objectives and current observing
program, and discuss the inventions and people who made it possible. We cite
detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space
Telescope Overview, 29 pages, 4 figure
Silencing of tryptamine biosynthesis for production of nonnatural alkaloids in plant culture
Natural products have long served as both a source and inspiration for pharmaceuticals. Modifying the structure of a natural product often improves the biological activity of the compound. Metabolic engineering strategies to ferment "unnatural" products have been enormously successful in microbial organisms. However, despite the importance of plant derived natural products, metabolic engineering strategies to yield unnatural products from complex, lengthy plant pathways have not been widely explored. Here, we show that RNA mediated suppression of tryptamine biosynthesis in Catharanthus roseus hairy root culture eliminates all production of monoterpene indole alkaloids, a class of natural products derived from two starting substrates, tryptamine and secologanin. To exploit this chemically silent background, we introduced an unnatural tryptamine analog to the production media and demonstrated that the silenced plant culture could produce a variety of novel products derived from this unnatural starting substrate. The novel alkaloids were not contaminated by the presence of the natural alkaloids normally present in C. roseus. Suppression of tryptamine biosynthesis therefore did not appear to adversely affect expression of downstream biosynthetic enzymes. Targeted suppression of substrate biosynthesis therefore appears to be a viable strategy for programming a plant alkaloid pathway to more effectively produce desirable unnatural products. Moreover, although tryptamine is widely found among plants, this silenced line demonstrates that tryptamine does not play an essential role in growth or development in C. roseus root culture. Silencing the biosynthesis of an early starting substrate enhances our ability to harness the rich diversity of plant based natural products