The 3D structure of rat DPPIV/CD26 as obtained by cryo-TEM and single particle analysis.
We present the three-dimensional structure of rat DPPIV/CD26, as determined by cryo-TEM and single particle analysis at a resolution of approximately 14A. The reconstruction confirms that the protein exists as a dimer, as predicted earlier. Since there are structural analogies to the serine peptidase POP, docking calculations of the two structures were performed. Although the docking showed a similar spatial organization (catalytic domain, beta-propeller, distal opening, central cavity), the detailed comparison revealed clear discrepancies. The most marked difference is a second (lateral) opening in DPPIV/CD26, which would enable direct access to the catalytic site. We therefore assume that substrate selectivity and binding rate are most probably driven by different mechanisms in DPPIV/CD26 and POP.
Ludwig
Kai
K
Forschungszentrum für Elektronenmikroskopie, Freie Universität Berlin, Fabeckstr. 36a, D-14195, Berlin-Dahlem, Germany.
Yan
Shuling
S
Fan
Hua
H
Reutter
Werner
W
Böttcher
Christoph
C
D000818:Animals; D020134:Catalytic Domain; D020285:Cryoelectron Microscopy / Q000379:methods; D019281:Dimerization; D018819:Dipeptidyl Peptidase 4 / Q000737:chemistry* / Q000378:metabolism; D007091:Image Processing, Computer-Assisted; D008958:Models, Molecular; D000085822:Prolyl Oligopeptidases; D051381:Rats; D012697:Serine Endopeptidases / Q000737:chemistry / Q000378:metabolism
D018819:Dipeptidyl Peptidase 4; D012697:Serine Endopeptidases; D000085822:Prolyl Oligopeptidases