Chitinase Chit62J4 Essential for Chitin Processing by Human Microbiome Bacterium _Clostridium parapurtiticum_ J4  
[PERSON]  
1 Laboratory of Structure and Function of Biomolecules, Institute of Biotechnology of the Czech Academy of Sciences, v. v. i., Boccw, Primyslova 395, 252 50 Vestec, Czech Republic; [EMAIL_ADDRESS] (J.D. ); [EMAIL_ADDRESS] (P.K. ); [EMAIL_ADDRESS] (T.S. ); [EMAIL_ADDRESS] (K.F.) [PERSON]  
1 Laboratory of Structure and Function of Biomolecules, Institute of Biotechnology of the Czech Academy of Sciences, v. v. i., Boccw, Primyslova 395, 252 50 Vestec, Czech Republic; [EMAIL_ADDRESS] (J.D. ); [EMAIL_ADDRESS] (P.K. ); [EMAIL_ADDRESS] (T.S. ); [EMAIL_ADDRESS] (K.F.) [PERSON]  
2 Department of Structural Analysis of Biomolecules, Institute of Macromolecular Chemistry of the Czech Academy of Sciences, v. v. i., Heyrovsky 3q, 2 162 06 Prague, Czech Republic; [EMAIL_ADDRESS] 2  
[PERSON]  
3 Laboratory of Structural Biology and Cell Signaling, Institute of Microbiology of the Czech Academy of Sciences, v. v. i., Boccw, Primyslova 395, 252 50 Vestec, Czech Republic; [EMAIL_ADDRESS] 3  
[PERSON]  
1 Laboratory of Structure and Function of Biomolecules, Institute of Biotechnology of the Czech Academy of Sciences, v. v. i., Boccw, Primyslova 395, 252 50 Vestec, Czech Republic; [EMAIL_ADDRESS] (J.D. ); [EMAIL_ADDRESS] (P.K. ); [EMAIL_ADDRESS] (T.S. ); [EMAIL_ADDRESS] (K.F.) [PERSON]  
4 Laboratory of Structure and Function of Biomolecules, Institute of Biotechnology of the Czech Academy of Sciences, v. v. i., Boccw, Primyslova 395, 252 50 Vestec, Czech Republic; [EMAIL_ADDRESS] 4  
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hydrolases and glycosyltransferases, with horizontal gene transfer and parallel gene loss being the expected primary mechanisms [5]. Gram-positive bacteria with low GC content form the most abundant bacterial group of the intestinal microbiome [1]. The distribution of individual microbiome species along the human colon is not uniform but is influenced by several factors. According to [6], the change of pH along the human gut may be responsible for a major drift within the human fecal bacterial community. In particular, the growth of a major group of Gram-negative bacteria is inhibited at mildly acidic pH, thus creating space for a lower pH-tolerant microorganism. Clostrtial clusters of bacteria are significantly more abundant at pH 5.5 compared to pH 6.5. However, when considering chitin digestion, colonization of insoluble polysaccharide fibers in the intestine may have a more complex pattern with respect to pH and its local variation, although detailed knowledge in this area is missing. However, a bacterium able to tolerate lower pH, typical for the proximal parts of the human colon, while digesting chitin or its derivatives, would have an advantage in competition with other intestinal microflora under specific conditions. Particular adaptations of human gut microbial enzymes under highly competitive microbiome conditions at the level of enzyme structure and function have been given little attention. However, one example is a study of \(\alpha\)-glucosidase from _Ruminococcus obeum_, capable of producing glucose from both isomaltose and maltose [7]. Chitinases (E.C. 3.2.1.14) are enzymes cleaving the \(\beta\)-1,4 bond of the natural polysaccharide chitin, composed of \(N\)-acetyl-d-glucosamine units (GlcNAcNAc)n. Bacterial chitinases have been studied and utilized for biotechnological purposes [8; 9]. Chitinases belong to glycosyl hydrolase (GH) classes, GH18, 19, 23 and 48 [10; 11]. The GH18 family contains archaeal, bacterial, eukaryotic, and viral chitinases, family 19 only bacterial and eukaryotic ones, and family 48 mainly eukaryotic ones.