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PR01650

Identifier
SECETRNLCASE  [View Relations]  [View Alignment]  
Accession
PR01650
No. of Motifs
4
Creation Date
23-DEC-2001
Title
Bacterial translocase SecE signature 
Database References
Literature References
1. BIEKER, K.L., PHILLIPS, G.J. AND SILHAVY, T.J. 
The sec and prl genes of Esherichia coli.
J.BIOENERG.BIOMEMBR. 22 291-310 (1990). 
 
2. DRIESSEN, A.J., FEKKES, P. AND VAN DER WOLK, J.P.
The Sec system.
CURR.OPIN.MICROBIOL. 1 216-222 (1998).
 
3. DOUVILLE, K., PRICE, A., EICHLER, J., ECONOMOU, A. AND WICKNER, W.
SecYEG and SecA are the stoichiometric components of preprotein translocase.
J.BIOL.CHEM. 270 20106-20111 (1995).
 
4. VEENENDAAL, A.K., VAN DER DOES, C. AND DRIESSEN, A.J.
Mapping the sites of interaction between SecY and SecE by cysteine scanning
mutagenesis.
J.BIOL.CHEM. 276 32559-32566 (2001).

Documentation
Secretion across the inner membrane in some Gram-negative bacteria occurs
via the preprotein translocase pathway. Proteins are produced in the 
cytoplasm as precursors, and require a chaperone subunit to direct them to 
the translocase component. [1]. From there, the mature proteins are either 
targeted to the outer membrane, or remain as periplasmic proteins [1]. The 
translocase protein subunits are encoded on the bacterial chromosome.
 
The translocase itself comprises 7 proteins, and consists of a chaperone 
(SecB), an ATPase (SecA), an integral membrane complex (SecY, SecE and SecG),
and two additional membrane proteins that promote the release of the mature
peptide into the periplasm (SecD and SecF) [1]. SecE, part of the main 
SecYEG translocase complex, is ~106 residues in length, and spans the 
inner membrane of the Gram-negative bacterial envelope [2]. Together with
SecY and SecG, SecE forms a multimeric channel through which preproteins
are translocated, using both proton motive forces and ATP-driven secretion
[3]. The latter is mediated by SecA. 
 
Recently, using cysteine scanning mutatgenesis, it has been found that the 
seventh transmembrane (TM) segment of SecY interacts with the third TM 
segment of SecE [4]. This alpha-helical cross-linking shows that SecY and 
SecE exist in a 1:1 stoichiometry in the complex. The SecE protein itself 
remains unaltered during preprotein insertion into the translocase pore,
retaining its tertiary structure [4].
 
SECETRNLCASE is a 4-element fingerprint that provides a signature for the
bacterial translocase SecE family. The fingerprint was derived from an
initial alignment of 4 sequences: the motifs were drawn from conserved 
regions spanning the C-terminal portion of the alignment - motif 1 encodes
putative TM domain 2; motif 2 spans the following cytoplasmic loop; motif 3
encodes putative TM domain 3; and motif 4 resides at the periplasmic
C-terminus. Two iterations on SPTR40_18f were required to reach convergence,
at which point a true set comprising 7 sequences was identified. A single
partial match was also found, Q9HWC3, a Pseudomonas aeruginosa SecE 
homologue that fails to make a significant match with motif 4.
Summary Information
   7 codes involving  4 elements
1 codes involving 3 elements
0 codes involving 2 elements
Composite Feature Index
47777
31110
20000
1234
True Positives
Q9CK83        SECE_BUCAI    SECE_ECOLI    SECE_HAEIN    
SECE_SALTY SECE_VIBAL SECE_VIBCH
True Positive Partials
Codes involving 3 elements
Q9HWC3
Sequence Titles
Q9CK83      SECE - Pasteurella multocida.                 
SECE_BUCAI Preprotein translocase secE subunit - Buchnera aphidicola (subsp. Acyrthosiphon pisum) (Acyrthosiphon pisum symbiotic bacterium).
SECE_ECOLI Preprotein translocase secE subunit - Escherichia coli, and Escherichia coli O157:H7.
SECE_HAEIN Preprotein translocase secE subunit - Haemophilus influenzae.
SECE_SALTY Preprotein translocase secE subunit - Salmonella typhimurium.
SECE_VIBAL Preprotein translocase secE subunit - Vibrio alginolyticus.
SECE_VIBCH Preprotein translocase secE subunit - Vibrio cholerae.

Q9HWC3 SECRETION PROTEIN SECE - Pseudomonas aeruginosa.
Scan History
SPTR40_18f 2  100  NSINGLE    
Initial Motifs
Motif 1  width=22
Element Seqn Id St Int Rpt
RALAVVILIAAAGGVALLTTKG SECE_ECOLI 44 44 -
RAAGVIVLIAAALGVAATTTKG SECE_VIBCH 45 45 -
RVIGMAIALVIAFILAAITNQG SECE_HAEIN 23 23 -
RIFIISCLMLCAIGTMIYTKKG SECE_BUCAI 44 44 -

Motif 2 width=21
Element Seqn Id St Int Rpt
GKATVAFAREARTEVRKVIWP SECE_ECOLI 65 -1 -
GKEAIVFARESRMEVRKVVWP SECE_VIBCH 66 -1 -
GTKARAFFNDSRTEARKVVWP SECE_HAEIN 44 -1 -
GKDILLYIVMSKKEMQKIIWP SECE_BUCAI 65 -1 -

Motif 3 width=21
Element Seqn Id St Int Rpt
ETLHTTLIVAAVTAVMSLILW SECE_ECOLI 89 3 -
ETMQTTLIVLAVSIVMALALW SECE_VIBCH 90 3 -
EARQTTLIVIGVTMIASLFFW SECE_HAEIN 68 3 -
ETLYTTFIVISVTIFISFILW SECE_BUCAI 89 3 -

Motif 4 width=17
Element Seqn Id St Int Rpt
WGLDGILVRLVSFITGL SECE_ECOLI 109 -1 -
WGIDGIMVRLVAFATGV SECE_VIBCH 110 -1 -
WAVDSIIVTVINFLTDL SECE_HAEIN 88 -1 -
WSIDSVIFRLIAFIISL SECE_BUCAI 109 -1 -
Final Motifs
Motif 1  width=22
Element Seqn Id St Int Rpt
RALAVVILIAAAGGVALLTTKG SECE_ECOLI 44 44 -
RALAVVILIAAAGGVALLTTKG SECE_SALTY 44 44 -
RAAGVIVLIAAALGVAATTTKG SECE_VIBCH 45 45 -
RAAGVVVLIAAALGVAATTTKG SECE_VIBAL 45 45 -
RVVGVVVLLLIALGLAALTNQG Q9CK83 53 53 -
RVIGMAIALVIAFILAAITNQG SECE_HAEIN 23 23 -
RIFIISCLMLCAIGTMIYTKKG SECE_BUCAI 44 44 -

Motif 2 width=21
Element Seqn Id St Int Rpt
GKATVAFAREARTEVRKVIWP SECE_ECOLI 65 -1 -
GKATVAFAREARTEVRKVIWP SECE_SALTY 65 -1 -
GKEAIVFARESRMEVRKVVWP SECE_VIBCH 66 -1 -
GKAAISFAKESRMEVRKVVWP SECE_VIBAL 66 -1 -
GVKARHFFSESRIELRKIVWP Q9CK83 74 -1 -
GTKARAFFNDSRTEARKVVWP SECE_HAEIN 44 -1 -
GKDILLYIVMSKKEMQKIIWP SECE_BUCAI 65 -1 -

Motif 3 width=21
Element Seqn Id St Int Rpt
ETLHTTLIVAAVTAVMSLILW SECE_ECOLI 89 3 -
ETLHTTLIVAAVTAVMSLILW SECE_SALTY 89 3 -
ETMQTTLIVLAVSIVMALALW SECE_VIBCH 90 3 -
ETMQTTLIVLAVSIVMALVLW SECE_VIBAL 90 3 -
EAMQTTLIVAGVTIVVSLILW Q9CK83 98 3 -
EARQTTLIVIGVTMIASLFFW SECE_HAEIN 68 3 -
ETLYTTFIVISVTIFISFILW SECE_BUCAI 89 3 -

Motif 4 width=17
Element Seqn Id St Int Rpt
WGLDGILVRLVSFITGL SECE_ECOLI 109 -1 -
WGLDGILVRLVSFITGL SECE_SALTY 109 -1 -
WGIDGIMVRLVAFATGV SECE_VIBCH 110 -1 -
WGIDGIMVRLVALATGV SECE_VIBAL 110 -1 -
WGLDSVIVALITFLTDL Q9CK83 118 -1 -
WAVDSIIVTVINFLTDL SECE_HAEIN 88 -1 -
WSIDSVIFRLIAFIISL SECE_BUCAI 109 -1 -