title: Functional characterization of the sucrose isomerase responsible for trehalulose production in plant-associated Pectobacterium species.
abstract: Fifty-three plant-associated microorganisms were investigated for their ability to convert sucrose to its isomers. These microorganisms included one Dickeya zeae isolate and 7 Enterobacter, 3 Pantoea, and 43 Pectobacterium species. Eleven out of the 53 strains (21%) showed the ability to transform sucrose to isomaltulose and trehalulose. Among those, Pectobacterium carotovorum KKH 3-1 showed the highest bioconversion yield (97.4%) from sucrose to its isomers. In this strain, the addition of up to 14% sucrose in the medium enhanced sucrose isomerase (SIase) production. The SIase activity at 14% sucrose (47.6 U/mg dcw) was about 3.6-fold higher than that of the negative control (13.3 U/mg dcw at 0% sucrose). The gene encoding SIase, which is comprised a 1776 bp open reading frame (ORF) encoding 591 amino acids, was cloned from P. carotovorum KKH 3-1 and expressed in Escherichia coli. The recombinant SIase (PCSI) was shown to have optimum activity at pH 6.0 and 40 °C. The reaction temperature significantly affected the ratio of sucrose isomers produced by PCSI. The amount of trehalulose increased from 47.5% to 79.1% as temperature was lowered from 50 °C to 30 °C, implying that SIase activity can be controlled by reaction temperature.
authors.affiliation: Graduate School of Biotechnology, and Institute of Life Science and Resources, Kyung Hee University, Yongin 446-701, Republic of Korea.
authors.forename: Cheon-Hyeon
authors.initials: CH
authors.lastname: Nam
authors.affiliation: Graduate School of Biotechnology, and Institute of Life Science and Resources, Kyung Hee University, Yongin 446-701, Republic of Korea.
authors.forename: Dong-Ho
authors.initials: DH
authors.lastname: Seo
authors.affiliation: Graduate School of Biotechnology, and Institute of Life Science and Resources, Kyung Hee University, Yongin 446-701, Republic of Korea.
authors.forename: Jong-Hyun
authors.initials: JH
authors.lastname: Jung
authors.affiliation: Department of Plant Medicine, Suncheon National University, Suncheon 540-950, Republic of Korea.
authors.forename: Young-Jin
authors.initials: YJ
authors.lastname: Koh
authors.affiliation: Department of Biology, Suncheon National University, Suncheon 540-950, Republic of Korea.
authors.forename: Jae-Sung
authors.initials: JS
authors.lastname: Jung
authors.affiliation: Microbial Safety Division, National Academy of Agricultural Science, Rural Development Administration, Suwon 441-707, Republic of Korea.
authors.forename: Sunggi
authors.initials: S
authors.lastname: Heu
authors.affiliation: Department of Horticultural Biotechnology, Kyung Hee University, Yongin 446-701, Republic of Korea.
authors.forename: Chang-Sik
authors.initials: CS
authors.lastname: Oh
authors.affiliation: Graduate School of Biotechnology, and Institute of Life Science and Resources, Kyung Hee University, Yongin 446-701, Republic of Korea. Electronic address: cspark@khu.ac.kr.
authors.forename: Cheon-Seok
authors.initials: CS
authors.lastname: Park
mesh_terms: D000595:Amino Acid Sequence; D001419:Bacteria / Q000201:enzymology; D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D001483:Base Sequence; D055162:Biocatalysis; D003001:Cloning, Molecular; D016384:Consensus Sequence; D018556:Crops, Agricultural / Q000382:microbiology; D004187:Disaccharides / Q000096:biosynthesis*; D004926:Escherichia coli; D005964:Glucosyltransferases / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007534:Isomaltose / Q000031:analogs & derivatives / Q000378:metabolism; D007536:Isomerism; D008969:Molecular Sequence Data; D016973:Pectobacterium carotovorum / Q000201:enzymology* / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D056910:Republic of Korea; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D013395:Sucrose / Q000378:metabolism*; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D004187:Disaccharides; D011993:Recombinant Fusion Proteins; D013395:Sucrose; D007534:Isomaltose; D005964:Glucosyltransferases; C116853:sucrose isomerase; C042003:trehalulose; C008189:isomaltulose
keywords: Isomaltulose; Pectobacterium sp.; Sucrose; Sucrose isomerase; Trehalulose