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3.A.1.109.1
α-Hemolysin exporter. HlyB has an (inactive?) N-terminal C39 peptidase-like domain (Lecher et al., 2011).  It is essential for secretion and interacts with the unfolded HlyA, thereby protecting it from cytoplasmic degradation (Lecher et al. 2012). Type 1 secretion systems (T1SSs)  extruding protein substrates following synthesis of the entire polypeptide. The E. coli hemolysin A secretion system has three membrane proteins - an inner membrane ABC transporter HlyB, an adaptor protein HlyD TC# 8.A.1.3.1), and an outer membrane porin TolC (TC# 1.B.17.1.1). All are required for secretion. Cryo-EM structures determined in two conformations revealed that the inner membrane complex is a hetero-dodecameric assembly comprising three HlyB homodimers and six HlyD subunits. Oligomerization of HlyB and HlyD is essential for protein secretion, and polypeptides translocate through a canonical ABC transporter pathway in HlyB (Zhao et al. 2022).  Type 1 secretion necessitates a tight interplay between all domains of the ABC transporter (Anlauf et al. 2024).

Accession Number:P08716
Protein Name:HlyB
Length:707
Molecular Weight:79673.00
Species:Escherichia coli [562]
Number of TMSs:8
Location1 / Topology2 / Orientation3: Cell inner membrane1 / Multi-pass membrane protein2
Substrate

Cross database links:

DIP: DIP-28120N
Pfam: PF00664    PF00005    PF03412   

Gene Ontology

GO:0016021 C:integral to membrane
GO:0005886 C:plasma membrane
GO:0030256 C:type I protein secretion system complex
GO:0005524 F:ATP binding
GO:0042626 F:ATPase activity, coupled to transmembrane m...
GO:0008233 F:peptidase activity
GO:0008565 F:protein transporter activity
GO:0030253 P:protein secretion by the type I secretion s...
GO:0006508 P:proteolysis
GO:0055085 P:transmembrane transport

References (5)

[1] “TolC, an Escherichia coli outer membrane protein required for hemolysin secretion.”  Wandersman C.et.al.   2112747
[2] “Topological and functional studies on HlyB of Escherichia coli.”  Gentschev I.et.al.   1552901
[3] “Analysis of the membrane organization of an Escherichia coli protein translocator, HlyB, a member of a large family of prokaryote and eukaryote surface transport proteins.”  Wang R.C.et.al.   1994034
[4] “Crystal structure of the nucleotide-binding domain of the ABC-transporter haemolysin B: identification of a variable region within ABC helical domains.”  Schmitt L.et.al.   12823972
[5] “Secretion of haemolysin by Escherichia coli.”  Mackman N.et.al.   3017638
Structure:
1MT0   1XEF   2FF7   2FFA   2FFB   2FGJ   2FGK   2PMK   3B5J      [...more]

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Predict TMSs (Predict number of transmembrane segments)
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FASTA formatted sequence 
1:	MDSCHKIDYG LYALEILAQY HNVSVNPEEI KHRFDTDGTG LGLTSWLLAA KSLELKVKQV 
61:	KKTIDRLNFI FLPALVWRED GRHFILTKIS KEVNRYLIFD LEQRNPRVLE QSEFEALYQG 
121:	HIILITSRSS VTGKLAKFDF TWFIPAIIKY RRIFIETLVV SVFLQLFALI TPLFFQVVMD 
181:	KVLVHRGFST LNVITVALSV VVVFEIILSG LRTYIFAHST SRIDVELGAK LFRHLLALPI 
241:	SYFESRRVGD TVARVRELDQ IRNFLTGQAL TSVLDLLFSL IFFAVMWYYS PKLTLVILFS 
301:	LPCYAAWSVF ISPILRRRLD DKFSRNADNQ SFLVESVTAI NTIKAMAVSP QMTNIWDKQL 
361:	AGYVAAGFKV TVLATIGQQG IQLIQKTVMI INLWLGAHLV ISGDLSIGQL IAFNMLAGQI 
421:	VAPVIRLAQI WQDFQQVGIS VTRLGDVLNS PTESYHGKLT LPEINGDITF RNIRFRYKPD 
481:	SPVILDNINL SIKQGEVIGI VGRSGSGKST LTKLIQRFYI PENGQVLIDG HDLALADPNW 
541:	LRRQVGVVLQ DNVLLNRSII DNISLANPGM SVEKVIYAAK LAGAHDFISE LREGYNTIVG 
601:	EQGAGLSGGQ RQRIAIARAL VNNPKILIFD EATSALDYES EHVIMRNMHK ICKGRTVIII 
661:	AHRLSTVKNA DRIIVMEKGK IVEQGKHKEL LSEPESLYSY LYQLQSD