TY - JOUR
T1 - Modified properties of alternan polymers arising from deletion of SH3-like motifs in Leuconostoc citreum ABK-1 alternansucrase
AU - Wangpaiboon, Karan
AU - Pitakchatwong, Chutamart
AU - Panpetch, Pawinee
AU - Charoenwongpaiboon, Thanapon
AU - Field, Robert A.
AU - Pichyangkura, Rath
N1 - Funding Information:
This work was funded by “Chulalongkorn University Graduate School scholarship, Doctoral Degree Chulalongkorn University 100 th Year Birthday Anniversary” , the 90 th Anniversary of Ratchadaphiseksomphot Endowment Fund of Chulalongkorn University (Grant GCUGR1125603018D ), Overseas Research Experience Scholarship for Graduate Students , the UK BBSRC Institute Strategic Program Molecules from Nature (MfN) [ BB/PO12523/1 ] and the John Innes Foundation . We gratefully thank the Starch and Cyclodextrin Research Unit, Department of Biochemistry, Faculty of Science, Chulalongkorn University for supporting on HPAEC-PAD; Prof. Dr. Suwabun Chirachanchai, Petroleum and Petrochemical College, Chulalongkorn University, for the Zetasizer Nano ZS analysis; Prof. Dr. Siriporn Damrongsakkul, Department of Chemical engineering, Faculty of Engineering, Chulalongkorn University, for the Vibro viscometer SV-10, and Dr. Paul Brett, Mzatabolite Analysis Platforms, John Innes Centre, Norwich Research Park for assisting with GC–MS.
Publisher Copyright:
© 2019 Elsevier Ltd
PY - 2019/9/15
Y1 - 2019/9/15
N2 - Alternansucrase (ALT, EC 2.4.1.140) catalyses the formation of an alternating 〈-1, 3/1, 6-linked glucan, with periodic branch points, from sucrose substrate. Beyond the catalytic domain, this enzyme harbours seven additional C-terminal SH3-like repeats. We herein generated two truncated alternansucrases, possessing deletions of three and seven adjacent SH3 motifs, giving Δ3SHALT and Δ7SHALT. Δ3SHALT and Δ7SHALT exhibited kcat/Km for transglycosylation activity 2.3- and 1.5-fold lower than wild-type ALT (WTALT), while hydrolysis was detected only in the truncated ALTs, oligosaccharide patterns and polymer glycosidic linkage were similar to that of WTALT. The viscosities of ALT polymers increase by ˜100-fold at 15% (w/v), with gel-like states formed at 12.5, 15.0, and 20.0% (w/v) produced by polymer from WTALT, Δ3SHALT, and Δ7SHALT, respectively. The average nanoparticle sizes of Δ3SHALT and Δ7SHALT polymers were 80 nm, compared to 90 nm from WTALT. In conclusion, even relatively subtle differences in the structure of ALT-produced alternan give rise to profound impact on the glucan polymer physicochemical properties.
AB - Alternansucrase (ALT, EC 2.4.1.140) catalyses the formation of an alternating 〈-1, 3/1, 6-linked glucan, with periodic branch points, from sucrose substrate. Beyond the catalytic domain, this enzyme harbours seven additional C-terminal SH3-like repeats. We herein generated two truncated alternansucrases, possessing deletions of three and seven adjacent SH3 motifs, giving Δ3SHALT and Δ7SHALT. Δ3SHALT and Δ7SHALT exhibited kcat/Km for transglycosylation activity 2.3- and 1.5-fold lower than wild-type ALT (WTALT), while hydrolysis was detected only in the truncated ALTs, oligosaccharide patterns and polymer glycosidic linkage were similar to that of WTALT. The viscosities of ALT polymers increase by ˜100-fold at 15% (w/v), with gel-like states formed at 12.5, 15.0, and 20.0% (w/v) produced by polymer from WTALT, Δ3SHALT, and Δ7SHALT, respectively. The average nanoparticle sizes of Δ3SHALT and Δ7SHALT polymers were 80 nm, compared to 90 nm from WTALT. In conclusion, even relatively subtle differences in the structure of ALT-produced alternan give rise to profound impact on the glucan polymer physicochemical properties.
KW - Alternan
KW - Alternansucrase
KW - Leuconostoc citreum
KW - SH3-like motif
UR - http://www.scopus.com/inward/record.url?scp=85066063894&partnerID=8YFLogxK
U2 - 10.1016/j.carbpol.2019.05.002
DO - 10.1016/j.carbpol.2019.05.002
M3 - Article
C2 - 31196527
AN - SCOPUS:85066063894
VL - 220
SP - 103
EP - 109
JO - Carbohydrate Polymers
JF - Carbohydrate Polymers
SN - 0144-8617
ER -