HAMAP

Accession	MF_01379
Dates	18-DEC-2007 (Created) 1-JUL-2011 (Last updated, Version 22)

Data class

Protein

Predictors

HAMAP; MF_01379; [distribution of match scores in UniProtKB];[seed alignment for MF_01379]

Names

PSII_PsbA_D1

Identifier

PSBA

Protein name

RecName: Full=Photosystem Q(B) protein; EC=1.10.3.9; AltName: Full=32 kDa thylakoid membrane protein; AltName: Full=Photosystem II protein D1; Flags: Precursor;

Gene name

psbA

FUNCTION: This is one of the two reaction center proteins of photosystem II (PSII) (By similarity).

CATALYTIC ACTIVITY: 2 H(2)O + 2 plastoquinone + 4 light = O(2) + 2 plastoquinol.

COFACTOR: The psbA/B heterodimer binds P680, the primary electron donor of PSII. It shares a non-heme iron and each subunit binds additional chlorophylls and pheophytin. PsbA provides most of the ligands for the Mn-cluster of the oxygen-evolving complex (By similarity).

SUBUNIT: The psbA/B heterodimer binds the P680 chlorophylls and subsequent electron acceptors. PSII consists of a core antenna complex that captures photons and an electron transfer chain that converts photonic excitation into a charge separation. PSII forms dimeric complexes (By similarity).

SUBCELLULAR LOCATION: Plastid, chloroplast thylakoid membrane; Multi-pass membrane protein (By similarity).

SUBCELLULAR LOCATION: Cell inner membrane; Multi-pass membrane protein (By similarity).

SUBCELLULAR LOCATION: Cellular thylakoid membrane; Multi-pass membrane protein (By similarity).

MISCELLANEOUS: Herbicides such as atrazine, BNT, diuron or ioxynil bind to Q(B) and block electron transport (By similarity).

MISCELLANEOUS: Cyanobacteria usually contain more than 2 copies of the psbA gene.

SIMILARITY: Belongs to the reaction center pufL/M/psbA/D family.

PROSITE	PS00244; REACTION_CENTER; 1;
Pfam	PF00124; Photo_RC; 1;
PRINTS	PR00256; REACTNCENTRE; 1;
TIGRFAMs	TIGR01151; psbA; 1;

Acetylation, Phosphoprotein.

Electron transport, Herbicide resistance, Iron, Membrane, Metal-binding, Oxidoreductase, Photosynthesis, Photosystem II.

Cell membrane, Cell inner membrane.

Thylakoid.

Transmembrane, Transport, Transmembrane helix.

GO:0009055; Molecular function: electron carrier activity.
GO:0005506; Molecular function: iron ion binding.
GO:0015979; Biological process: photosynthesis.
GO:0055114; Biological process: oxidation-reduction process.

GO:0009535; Cellular component: chloroplast thylakoid membrane.

GO:0005886; Cellular component: plasma membrane.

GO:0042651; Cellular component: thylakoid membrane.

From: PSBA_SPIOL (P69560)
Key		From		To		Description		Condition		FTGroup
TRANSMEM		36		56		Helical; (Potential)
TRANSMEM		109		129		Helical; (Potential)
TRANSMEM		141		164		Helical; (Potential)
TRANSMEM		192		218		Helical; (Potential)
TRANSMEM		269		289		Helical; (Potential)
SITE		344		345		Cleavage; by CtpA (By similarity)		A-[AS]
CHAIN		1		344		Photosystem Q(B) protein

Key		From		To		Description		Condition		FTGroup
PROPEP		345		Cter		Potential

Key		From		To		Description		Condition		FTGroup
METAL		215		215		Iron; shared with heterodimeric partner (By similarity)		H
METAL		272		272		Iron; shared with heterodimeric partner (By similarity)		H

Key		From		To		Description		Condition		FTGroup
MOD_RES		2		2		N-acetylthreonine (By similarity)		T
MOD_RES		2		2		Phosphothreonine (By similarity)		T

Size range:	340-363 amino acids
Related UniRules:	None
Template:	P0A444 (PSBA1_THEEB); P69560 (PSBA_SPIOL); P07753 (PSBA_CHLRE); P16033 (PSBA2_SYNY3): [Recover all]
Scope:	Bacteria; Cyanobacteria Plastid
Fusion:	Nter: None; Cter: None
Duplicate:	in ACAM1, NOSS1, ANAVT, MICAN, THEEB, SYNEN, SYNJA, SYNP2, SYNP6, SYNE7, SYNPW, SYNPX, SYNS3, SYNY3, TRIEI
Plasmid encoded:	None
Comments:	C-terminal cleavage of D1 by the C-terminal processing protese (CtpA) within the thylakoid lumen is required for ligation of the manganese cluster and association of the oxygen-evolving complex. EUGGR, BIGNA, LEPTE, STAPU and some dinoflagellates are already this length and thus do not seem to be encoded as precursor proteins. One copy in ACAM1 (A5A8K9) and in ANAVT (Q3M5L6) do not have the cleavage site. D1 is very photosensitive and there is a mechanism to replace photodamaged D1.