ジャーナル: Nat Commun / 年: 2018 タイトル: Cryo-EM structures of human STEAP4 reveal mechanism of iron(III) reduction. 著者: Wout Oosterheert / Laura S van Bezouwen / Remco N P Rodenburg / Joke Granneman / Friedrich Förster / Andrea Mattevi / Piet Gros / 要旨: Enzymes of the six-transmembrane epithelial antigen of the prostate (STEAP) family reduce Fe and Cu ions to facilitate metal-ion uptake by mammalian cells. STEAPs are highly upregulated in several ...Enzymes of the six-transmembrane epithelial antigen of the prostate (STEAP) family reduce Fe and Cu ions to facilitate metal-ion uptake by mammalian cells. STEAPs are highly upregulated in several types of cancer, making them potential therapeutic targets. However, the structural basis for STEAP-catalyzed electron transfer through an array of cofactors to metals at the membrane luminal side remains elusive. Here, we report cryo-electron microscopy structures of human STEAP4 in absence and presence of Fe-NTA. Domain-swapped, trimeric STEAP4 orients NADPH bound to a cytosolic domain onto axially aligned flavin-adenine dinucleotide (FAD) and a single b-type heme that cross the transmembrane-domain to enable electron transfer. Substrate binding within a positively charged ring indicates that iron gets reduced while in complex with its chelator. These molecular principles of iron reduction provide a basis for exploring STEAPs as therapeutic targets.
pH: 5.5 / 詳細: 25 mM MES pH 5.5 200 mM NaCl 0.08% digitonin (w/v)
緩衝液成分
ID
濃度
名称
式
Buffer-ID
1
200mM
sodiumchloride
NaCl
1
2
25mM
2-(N-morpholino)ethanesulfonic acid
C6H13NO4S
1
3
0.08 % (w/v)
DIGITONIN
C56H92O29
1
試料
濃度: 4 mg/ml / 包埋: NO / シャドウイング: NO / 染色: NO / 凍結: YES 詳細: human STEAP4 was purified from the HEK293 GNTI- cell membrane through Strep-affinity chromatography and size-exclusion chromatography (SEC). After SEC in digitonin, the sample was ...詳細: human STEAP4 was purified from the HEK293 GNTI- cell membrane through Strep-affinity chromatography and size-exclusion chromatography (SEC). After SEC in digitonin, the sample was monodisperse. Cofactors NADPH and FAD were added before grid freezing.