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PDBsum entry 1ci3
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Electron transport
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PDB id
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1ci3
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Contents |
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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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Structure of the soluble domain of cytochrome f from the cyanobacterium phormidium laminosum.
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Authors
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C.J.Carrell,
B.G.Schlarb,
D.S.Bendall,
C.J.Howe,
W.A.Cramer,
J.L.Smith.
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Ref.
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Biochemistry, 1999,
38,
9590-9599.
[DOI no: ]
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PubMed id
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Abstract
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Cytochrome f from the photosynthetic cytochrome b(6)f complex is unique among
c-type cytochromes in its fold and heme ligation. The 1. 9-A crystal structure
of the functional, extrinsic portion of cytochrome f from the thermophilic
cyanobacterium Phormidium laminosum demonstrates that an unusual buried chain of
five water molecules is remarkably conserved throughout the biological range of
cytochrome f from cyanobacteria to plants [Martinez et al. (1994) Structure 2,
95-105]. Structure and sequence conservation of the cytochrome f extrinsic
portion is concentrated at the heme, in the buried water chain, and in the
vicinity of the transmembrane helix anchor. The electrostatic surface potential
is variable, so that the surface of P. laminosum cytochrome f is much more
acidic than that from turnip. Cytochrome f is unrelated to cytochrome c(1), its
functional analogue in the mitochondrial respiratory cytochrome bc(1) complex,
although other components of the b(6)f and bc(1) complexes are homologous.
Identical function of the two complexes is inferred for events taking place at
sites of strong sequence conservation. Conserved sites throughout the entire
cytochrome b(6)f/bc(1) family include the cluster-binding domain of the Rieske
protein and the heme b and quinone-binding sites on the electrochemically
positive side of the membrane within the b cytochrome, but not the putative
quinone-binding site on the electrochemically negative side.
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Secondary reference #1
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Title
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The heme redox center of chloroplast cytochrome f is linked to a buried five-Water chain.
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Authors
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S.E.Martinez,
D.Huang,
M.Ponomarev,
W.A.Cramer,
J.L.Smith.
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Ref.
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Protein Sci, 1996,
5,
1081-1092.
[DOI no: ]
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PubMed id
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Figure 2.
Fig. 2. Color stereo ribbon drawing of cytochromef. Arg 50, the last
residue showing order in the electron density map, whichis
to the trans-membrane anchor domain(not shown), is at the bottom cen-
ter. The heme is shown in ball-and-stick representation with porphyrin
ring in green and hemeFein orange-brown. The five-water chain
isin red. clarity,theTyr 1 and His 25 heme ligands are not shown.
he position of Lys 66 is marked, with its side chain shown in
he nearby side chains of ys 58 and Lys 65 thatcontribute to posi-
tively charged surface region re lso in green.
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Figure 4.
Fi. 4. Perpendicularstereo views of thepacking of theheme groupagainstthecore of thelargedomain. A: Edge-on view of
theheme. B: Front view of heheme.Parts of &sheet C, C', and F (see text),utilizingthelabeledresidues, form apocket for
the A-B hemeedge.
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The above figures are
reproduced from the cited reference
which is an Open Access publication published by the Protein Society
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