Chitinase Chit62J4 essential for chitin processing by human microbiome bacterium clostridium paraputrificum J4

0550734 - BTÚ 2022 RIV CH eng J - Journal Article
Dohnálek, Jan - Dušková, Jarmila - Tishchenko, Galina - Kolenko, Petr - Skálová, Tereza - Novák, Petr - Fejfarová, Karla - Šimůnek, Jiří
Chitinase Chit62J4 essential for chitin processing by human microbiome bacterium clostridium paraputrificum J4.
Molecules. Roč. 26, č. 19 (2021), č. článku 5978. E-ISSN 1420-3049
R&D Projects: GA MŠMT(CZ) ED1.1.00/02.0109; GA ČR(CZ) GA20-12109S
Research Infrastructure: CIISB - 90043; CIISB II - 90127
Institutional support: RVO:86652036 ; RVO:61389013 ; RVO:61388971 ; RVO:67985904
Keywords : Adaptation to the environment * Chitinase * Exochitinase * Glycosyl hydrolase family 18 * Human commensal bacterium
OECD category: Biochemistry and molecular biology; Polymer science (UMCH-V)
Impact factor: 4.927, year: 2021
Method of publishing: Open access
https://www.mdpi.com/1420-3049/26/19/5978

Commensal bacterium Clostridium paraputrificum J4 produces several extracellular chiti-nolytic enzymes including a 62 kDa chitinase Chit62J4 active toward 4-nitrophenyl N,N′-diacetyl-β-D-chitobioside (pNGG). We characterized the crude enzyme from bacterial culture fluid, recombinant enzyme rChit62J4, and its catalytic domain rChit62J4cat. This major chitinase, securing nutrition of the bacterium in the human intestinal tract when supplied with chitin, has a pH optimum of 5.5 and processes pNGG with Km = 0.24 mM and kcat = 30.0 s−1 . Sequence comparison of the amino acid sequence of Chit62J4, determined during bacterial genome sequencing, characterizes the enzyme as a family 18 glycosyl hydrolase with a four-domain structure. The catalytic domain has the typical TIM barrel structure and the accessory domains—2x Fn3/Big3 and a carbohydrate binding module—that likely supports enzyme activity on chitin fibers. The catalytic domain is highly homologous to a single-domain chitinase of Bacillus cereus NCTU2. However, the catalytic profiles significantly differ between the two enzymes despite almost identical catalytic sites. The shift of pI and pH optimum of the commensal enzyme toward acidic values compared to the soil bacterium is the likely environmental adaptation that provides C. paraputrificum J4 a competitive advantage over other commensal bacteria.
Permanent Link: http://hdl.handle.net/11104/0326061