Price, D.R.G., Karley, A.J., Ashford, D.A., Isaacs, H.V., Pownall, M.E., Wilkinson, H.S., Gatehouse, J.A. and Douglas, A.E. (2007) Molecular characterisation of a candidate gut sucrase in the pea aphid, Acyrthosiphon pisum. Insect Biochemistry and Molecular Biology, 37 (4). pp. 307-317. ISSN 0965-1748
The hydrolysis of sucrose, the principal dietary source of carbon for aphids, is catalysed by a gut α-glucosidase/transglucosidase activity. An α-glucosidase, referred to as APS1, was identified in both a gut-specific cDNA library and a sucrase-enriched membrane preparation from guts of the pea aphid Acyrthosiphon pisum by a combination of genomic and proteomic techniques. APS1 contains a predicted signal peptide, and has a predicted molecular mass of 68 kDa (unprocessed) or 66.4 kDa (mature protein). It has amino acid sequence similarity to α-glucosidases (EC 18.104.22.168) of glycoside hydrolase family 13 in other insects. The predicted APS1 protein contains two domains: an N-terminal catalytic domain, and a C-terminal hydrophobic domain. In situ localisation and RT-PCR studies revealed that APS1 mRNA was expressed in the gut distal to the stomach, the same localisation as sucrase activity. When expressed heterologously in Xenopus embryos, APS1 was membrane-bound and had sucrase activity. It is concluded that APS1 is a dominant, and possibly sole, protein mediating sucrase activity in the aphid gut.
|Institution:||The University of York|
|Academic Units:||The University of York > Biology (York)|
|Depositing User:||York RAE Import|
|Date Deposited:||24 Jul 2009 14:26|
|Last Modified:||24 Jul 2009 14:26|