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SUMMARY:LMB Seminar: Biosynthesis and degradation of the underappreciated 
 green polymer cyanophycin - Martin Schmeing\, Ph.D.\, James McGill Profess
 or\, Department of Biochemistry and Directeur\, Centre de recherche en bio
 logie structurale\, McGill University
DTSTART:20240404T100000Z
DTEND:20240404T110000Z
UID:TALK211870@talks.cam.ac.uk
CONTACT:Scientific Meetings Co-ordinator
DESCRIPTION:Cyanophycin is a biopolymer consisting of a poly-aspartate bac
 kbone and arginines linked to each Asp side chain though isopeptide bonds.
  Used in bacteria for storage of fixed nitrogen\, carbon and energy\, chai
 ns of cyanophycin of 80-400 β-Asp-Arg dipeptide residues coalesce into in
 ert\, membrane-less granules which can occupy most of the volume of a cell
 . Cyanophycin has a variety of potential green industrial and biomedical a
 pplications\, which could be potentiated by the understanding and biochemi
 cal engineering of the enzymes involved in its metabolism. Cyanophycin is 
 made by cyanophycin synthetase 1 or 2 through ATP-dependent polymerization
  of Asp and Arg\, or β-Asp-Arg\, respectively. It is degraded into dipept
 ides by specialized exo-cyanophycinases\, and these dipeptidase are hydrol
 yzed into free amino acids by nonspecific isoaspartyl dipeptidases. I will
  share highlights of our structural and functional studies of cyanophycin 
 biosynthesis and degradation\, which led to surprising discoveries: Our st
 ructures and biochemical assays of the cyanophycin synthetase 1 revealed i
 t to be a remarkable\, multi-domain\, multi-functional biosynthetic machin
 e and uncovered a hidden hydrolytic active site that is crucial for rapid 
 biosynthesis. We also showed that cyanophycin synthetase 2 can assume seve
 ral elegant architectures that influence its synthetic activity. Further\,
  we discovered and characterized a novel\, large family of isoaspartyl dip
 eptidases dedicated to cyanophycin metabolism\, which allows the human pat
 hogen Pseudomonas aeruginosa to use β-Asp-Arg as a sole carbon source\, a
 nd as good a sole nitrogen source as ammonium. Bioinformatics results unde
 rscore how common it is for bacteria to be cyanophycin producers or scaven
 gers\, much more so than currently appreciated. \n\nReferences: \nSharon I
 \, McKay G\, Nguyen D\, Schmeing TM. Discovery of cyanophycin dipeptide hy
 drolase enzymes suggests widespread utility of the natural biopolymer cyan
 ophycin. PNAS 2023 120 (8)\, e2216547120. PMID: 36800389 \nSharon I\, Pinu
 s S\, Grogg M\, Moitessier N\, Hilvert D\, Schmeing TM. A cryptic third ac
 tive site in cyanophycin synthetase creates primers for polymerization. Na
 t Comm 2022 Jul 7\; 13:3923. PMID: 35798723\nSharon I\, Haque AH\, Grogg M
 \, Lahiri I\, Seebach D\, Leschziner AE\, Hilvert D\, Schmeing TM. Structu
 res and function of the amino acid polymerase cyanophycin synthetase. Nat 
 Chem Biol 2021 Oct\; 17\, 1101–1110. PMID: 34385683.
LOCATION:In person in the LMB's Klug Seminar Room (CB2 0QH) and via Zoom\,
  link: https://mrc-lmb-cam-ac-uk.zoom.us/j/96568201418?pwd=c3F0aCtOeTVwR3I
 yQzZYdkxoWHdPUT09
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