Multiple crystal forms of hexokinase I: new insights regarding conformational dynamics, subunit interactions, and membrane association.
Hexokinase I is comprised of homologous N- and C-terminal domains, and binds to the outer membrane of mitochondria. Reported here is the structure of a new crystal form of recombinant human hexokinase I, which complements existing crystal structures. Evidently, in some packing environments and even in the presence of glucose and glucose 6-phosphate the N-terminal domain (but not the C-terminal domain) can undergo oscillations between closed and partially opened conformations. Subunit interfaces, present in all known crystal forms of hexokinase I, promote the formation of linear chains of hexokinase I dimers. Presented is a model for membrane-associated hexokinase I, in which linear chains of hexokinase I dimers are stabilized by interactions with mitochondrial porin.
Aleshin
A E
AE
Department of Biochemistry and Biophysics, Iowa State University, Ames 50011, USA.
Fromm
H J
HJ
Honzatko
R B
RB
D002462:Cell Membrane / Q000378:metabolism*; D018360:Crystallography, X-Ray; D006593:Hexokinase / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism
D008565:Membrane Proteins; D011994:Recombinant Proteins; D006593:Hexokinase