Molecular cloning and expression analysis of the starch-branching enzyme III gene from common wheat (Triticum aestivum ).
The starch-branching enzyme (SBE) catalyzes the formation of branch points by cleaving the α-1,4 linkage in polyglucans and reattaching the chain via an α-1,6 linkage. Three types of SBE isoforms (SBEI, SBEII, and SBEIII) exist in higher plants, with the number of SBE isoforms being species-specific. This study isolated the SBEIII cDNA sequence (3,780 bp), designated TaSBEIII (accession no. JQ346193), from common wheat (Triticum aestivum L.) using the RACE method, revealing that the SBEIII gene exists in common wheat. The open reading frame of TaSBEIII was 2,748 bp. The predicted protein of 916 amino acids contained the specific characteristics of the SBEIII protein: four highly conserved regions and a central (α/β)(8) barrel domain. The SBE activity of the protein expressed in Escherichia coli (BL21) was also measured and verified. During the wheat grain filling period, TaSBEIII was constitutively expressed. The role of the TaSBEIII gene in starch synthesis is discussed.
Key Laboratory of Physiology, Ecology and Genetic Improvement of Food Crops in Henan Province, National Engineering Research Centre for Wheat, Henan Agricultural University, Zhengzhou 450002, China. zkangg@163.com
Guozhang
G
Kang
Shuyi
S
Li
Mengqin
M
Zhang
Huifang
H
Peng
Chenyang
C
Wang
Yunji
Y
Zhu
Tiancai
T
Guo
D015061:1,4-alpha-Glucan Branching Enzyme / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D001483:Base Sequence; D055162:Biocatalysis; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000302:isolation & purification; D004926:Escherichia coli / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012639:Seeds / Q000235:genetics; D014908:Triticum / Q000201:enzymology* / Q000235:genetics*
D018076:DNA, Complementary; D015061:1,4-alpha-Glucan Branching Enzyme