Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Record number 401186
Title Analysis of the polymerization initiation and activity of Pasteurella multocida heparosan synthase PmHS2, an enzyme with glycosyltransferase and UDP-sugar hydrolase activity
Author(s) Chavaroche, A.A.E.; Broek, L.A.M. van den; Springer, J.; Boeriu, C.; Eggink, G.
Source Journal of Biological Chemistry 286 (2011)3. - ISSN 0021-9258 - p. 1777 - 1785.
Department(s) Bioprocess Engineering
FBR Sustainable Chemistry & Technology
FBR Bioconversion
Publication type Refereed Article in a scientific journal
Publication year 2011
Keyword(s) hyaluronan synthase - chemoenzymatic synthesis - identification - biosynthesis - glycosidases - transferase - mechanism - polymers - distinct - sulfate
Abstract Heparosan synthase catalyzes the polymerization of heparosan [-4GlcUAß1-4GlcNAca1-]n by transferring alternatively the monosaccharide units from UDP-GlcUA and UDP-GlcNAc to an acceptor molecule. Details on the heparosan chain initiation by Pasteurella multocida heparosan synthase PmHS2 and its influence on the polymerization process have not been reported yet. By site directed mutagenesis of PmHS2, the single action transferases PmHS2-GlcUA+ and PmHS2-GlcNAc+ were obtained. When incubated together in the standard polymerization conditions, the PmHS2-GlcUA+/PmHS2-GlcNAc+ showed comparable polymerization properties as determined for PmHS2. We investigated the first step occurring in heparosan chain initiation by the use of the single action transferases and by studying the PmHS2 polymerization process in the presence of heparosan templates and various UDP-sugar concentrations. We observed that PmHS2 favored the initiation of the heparosan chains when incubated in the presence of an excess of UDP-GlcNAc. It resulted in a higher number of heparosan chains with a lower average molecular weight or in the synthesis of two distinct groups of heparosan chain length, in the absence or in the presence of heparosan templates, respectively. These data suggest that PmHS2 transfers GlcUA from UDP-GlcUA moiety to a UDP-GlcNAc acceptor molecule to initiate the heparosan polymerization; as a consequence not only the UDP-sugar concentration but also the amount of each UDP-sugar is influencing the PmHS2 polymerization process. In addition, it was shown that PmHS2 hydrolyzes the UDP-sugars; UDP-GlcUA being more degraded than UDP-GlcNAc. However, PmHS2 incubated in the presence of both UDP-sugars favors the synthesis of heparosan polymers over the hydrolysis of UDP-sugars
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