{PDOC51933}
{PS51933; EUTK_C}
{BEGIN}
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* EutK-Ctail domain profile *
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Bacterial microcompartments   (BMCs)   are   large   proteinaceous  structures
comprised of a roughly icosahedral shell and a series of encapsulated enzymes.
They function  as  organelles  by  sequestering particular metabolic processes
within the  cell.  A  shell  or  capsid,  which  is composed of a few thousand
protein subunits,  surrounds  a  series  of  sequentially  acting  enzymes and
controls the diffusion of substrates and products (including toxic or volatile
intermediates) into  and  out  of  the  lumen.  One BMC, which is dedicated to
ethanolamine utilization  (Eut),  is  present  in  several bacteria, including
Salmonella enterica  and  Escherichia  coli.  The cellular function of the Eut
microcompartment is to metabolize ethanolamine without allowing the release of
acetaldehyde into  the  cytosol, thus mitigating the potentially toxic effects
of excess  aldehyde  in the bacterial cytosol and also preventing the volatile
acetaldehyde from  diffusing across the cell membrane and leading to a loss of
carbon. The  shells  of  BMCs are made primarily of a family of proteins whose
structural core  is the BMC domain (see <PDOC00876>). Four homologous proteins
(EutS, EutL, EutK, and EutM) are thought to be the major shell constituents of
a functionally  complex Eut microcompartment. A fifth protein, EutN is a minor
shell component but not homologous to the BMC shell proteins (see <PDOC51932>)
[1].

The EutK  shell  protein  is  distinct  among  the  shell  proteins in the Eut
microcompartment. First,  although all other BMC proteins studied to date form
hexamers (or  pseudohexamers,  like  EutL), EutK is a monomer in solution. The
apparent inability  of EutK to assemble into a hexamer by itself suggests that
different BMC paralogs might form mixed hexamers during assembly of the shell.
Second, EutK  has an extra protein domain (EutK-Ctail) of about 60 amino acids
following the  conserved  BMC  domain.  The EutK-Ctail domain is a helix-turn-
helix domain (see <PDB:3I71>) that might bind nucleic acids [1].

The profile we developed covers the entire EutK-Ctail domain.

-Sequences known to belong to this class detected by the profile: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.
-Last update: July 2020 / First entry.

[ 1] Tanaka S., Sawaya M.R., Yeates T.O.
     "Structure and mechanisms of a protein-based organelle in Escherichia
     coli."
     Science 327:81-84(2010).
     PubMed=20044574; DOI=10.1126/science.1179513

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