September 2013

Gut bacteria may be a source of male steroid hormones

Looks like there is more than one fount for male steroid hormones in the body. In a paper recently out in the Journal of Lipid Research, researchers show that a bacterial species converts glucocorticoids into androgens, a group of male steroid hormones. The implication is that the host endocrine system may not be the only source of androgens and other regulatory molecules: The gut microbiome may be another.


Introducing the monkey sperm proteome

We now have the sperm proteome of a primate. In a paper in Molecular & Cellular Proteomics, researchers describe the sperm proteome of the rhesus macaque, the first primate to have its sperm proteome analyzed. Sperm proteomes from nonprimate species, such as rats, mice and fruit flies, already have been determined. “For comparative evolutionary and functional genomics studies, a primate sperm proteome was highly desirable to include in this growing list of sperm proteomes,” explains Tim Karr at Arizona State University.


Proteins need chaperones, too

“I remember walking down the hill to grab breakfast after an overnight fire drill with putting up image plates, shooting X-rays, then fetching the plates and putting them into the Fuji scanner at the F1 beamline … thinking, ‘This is really going to change our understanding of this machine.’” This is how Arthur Horwich relates the excitement during his first data collection on the GroEL protein at the Cornell High Energy Synchrotron Source. Describing his 20-year scientific adventure with the protein-folding machine in his recent Reflections article in The Journal of Biological Chemistry, Horwich takes readers through the initial discovery of the chaperonin, its structural analyses and elucidation of its mechanism.


Chlamydial virulence factor structure 'very odd indeed'

A protein secreted by Chlamydia trachomatis, the bacterium that causes chlamydia, has an unusual structure, according to scientists in the School of Medicine at The University of Texas Health Science Center San Antonio. The shape of the protein Pgp3 is distinctive — sort of like an Eiffel Tower of proteins.


Making a new ring every 20 minutes

Cell division, the final stage of the bacterial cell cycle, involves a network of molecules to control the position of the division machinery, the divisome, at midcell. In E. coli, a bacterium that lives in our gut, the initial assembly of the division machinery requires three major proteins, FtsZ, FtsA and ZipA, and together these proteins form the proto-ring at midcell. In a recent minireview published in The Journal of Biological Chemistry, researchers at the Centro Nacional de Biotecnologia in Madrid describe the importance of these proteins in the formation, maturation, stabilization and function of the E. coli division machinery.


Plants use a network of modifying enzymes to control hormone action

The effects of plant hormones, such as ethylene, auxins or gibberellins, are crucial to the proper growth and development of plants. Equally important, however, is the biochemical regulation of plant hormones in synthesis and modification. In a recent minireview published in The Journal of Biological Chemistry, Corey S. Westfall and colleagues at Washington University in St. Louis highlight the key enzymatic players in hormone regulation, noting the remarkable evolutionary conservation of families of regulatory enzymes as well as the intricate network needed to turn hormones on and off at just the right time.


Thematic series explores biochemical diversity of cytochrome P450 enzymes

A recent thematic series on cytochromes P450 in The Journal of Biological Chemistry consists of four minireviews covering new trends in P450 research and the many roles they play in disease. As important catalysts involved in hormone and drug biochemistry, these diverse enzymes are the center of attention in a number important fields. In his introduction to the series, coordinating editor F. Peter Guengerich of Vanderbilt University illustrates how the P450 field has matured over the past 50 years. “With (more than) 18,000 known P450 sequences available and the number increasingly rapidly,” Guengerich writes, “it is humbling to realize that we understand the functions of only a fraction of these P450s.”

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