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Maltoporin

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LamB porin
Structure of maltoporin fromSalmonella typhimurium.[1]
Identifiers
SymbolLamB
PfamPF02264
InterProIPR003192
SCOP22mpr/SCOPe/SUPFAM
TCDB1.B.3
OPM superfamily32
OPM protein2mpr
CDDcd01346
Available protein structures:
Pfam structures/ECOD
PDBRCSB PDB;PDBe;PDBj
PDBsumstructure summary
PDB1a0sQ:97-5051oh2R:97-5051a0tP:97-505

1mprA:28-4522mprB:28-4521mpmA:28-446 1mpoC:28-4461af6A:28-4461malC:28-446

1mpqB:28-4461mpnB:28-446

Maltoporins(orLamB porins) arebacterial outer membraneproteinsof theporinfamily.Maltoporin forms a trimeric structure which facilitates thediffusionofmaltodextrinsacross the outer membrane ofGram-negativebacteria.The membrane channel is formed by an antiparallelbeta-barrel.[2]

Most pores used for diffusion contain only 16 antiparallel strands, but maltoporin has 18. The structure of maltoporin contains long loops and short turns. The long loops are in contact with the cell exterior and the turns are in contact with theperiplasm.This channel is involved in sugar transport. The sugar initially binds to the first greasy residue withvan der Waals forces.The sugar continues through the channel by guided diffusion of the sugar along the greasy residues which form a "slide".[3]

Maltoporin's original name was LamB because it is abacteriophage lambdareceptor. This channel is specific for maltosaccharides, whose affinity for the channel increases as the length of the chain increases.[3]

References

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  1. ^Meyer JE, Hofnung M, Schulz GE (March 1997). "Structure of maltoporin from Salmonella typhimurium ligated with a nitrophenyl-maltotrioside".J. Mol. Biol.266(4): 761–75.doi:10.1006/jmbi.1996.0823.PMID9102468.
  2. ^Schirmer T, Rosenbusch JP, Keller TA, Wang YF (1995). "Structural basis for sugar translocation through maltoporin channels at 3.1 A resolution".Science.267(5197): 512–514.doi:10.1126/science.7824948.PMID7824948.S2CID44587780.
  3. ^abRanquin, An; Van Gelder, Patrick (October 2004)."Maltoporin: sugar for physics and biology".Research in Microbiology.155(8): 611–616.doi:10.1016/j.resmic.2004.05.007.