 |
PDBsum entry 3ee6
|
|
|
|
References listed in PDB file
|
 |
|
Key reference
|
|
|
Title
|
|
Structure of tripeptidyl-Peptidase i provides insight into the molecular basis of late infantile neuronal ceroid lipofuscinosis.
|
|
|
Authors
|
|
A.Pal,
R.Kraetzner,
T.Gruene,
M.Grapp,
K.Schreiber,
M.Grønborg,
H.Urlaub,
S.Becker,
A.R.Asif,
J.Gärtner,
G.M.Sheldrick,
R.Steinfeld.
|
|
|
Ref.
|
|
J Biol Chem, 2009,
284,
3976-3984.
[DOI no: ]
|
|
|
PubMed id
|
|
|
|
|
Note: In the PDB file this reference is
annotated as "TO BE PUBLISHED". The citation details given above have
been manually determined.
|
|
|
|
Abstract
|
|
|
Late infantile neuronal ceroid lipofuscinosis, a fatal neurodegenerative disease
of childhood, is caused by mutations in the TPP1 gene that encodes
tripeptidyl-peptidase I. We show that purified TPP1 requires at least partial
glycosylation for in vitro autoprocessing and proteolytic activity. We
crystallized the fully glycosylated TPP1 precursor under conditions that implied
partial autocatalytic cleavage between the prosegment and the catalytic domain.
X-ray crystallographic analysis at 2.35 angstroms resolution reveals a globular
structure with a subtilisin-like fold, a Ser475-Glu272-Asp360 catalytic triad,
and an octahedrally coordinated Ca2+-binding site that are characteristic
features of the S53 sedolisin family of peptidases. In contrast to other S53
peptidases, the TPP1 structure revealed steric constraints on the P4 substrate
pocket explaining its preferential cleavage of tripeptides from the
unsubstituted N terminus of proteins. Two alternative conformations of the
catalytic Asp276 are associated with the activation status of TPP1. 28
disease-causing missense mutations are analyzed in the light of the TPP1
structure providing insight into the molecular basis of late infantile neuronal
ceroid lipofuscinosis.
|
|
|
|
|
|
|
|
Figure 4.
Topology diagram of the TPP1 structure showing the prosegment
(Ser^20-Ser^180) and the catalytic domain
(His^197-Pro^563).α-Helices are labeled α and are represented
by cylinders, and β-strands are labeled β and represented by
arrows. Residues that are involved in the catalytic mechanism
are marked by red letters; the 6 cysteine residues that form
disulfide bridges are colored yellow on black background, and
the asparagine residues that carry N-linked oligosaccharides are
highlighted by a turquoise background. No density could be
observed for a possible glycosylation at Asn^222 (highlighted
with gray background). The linker region (Ser^181-Leu^196) was
poorly defined (gray letters). The first amino acid R of the
purification tag RSHHHHHH is displayed in gray.
|
|
Figure 9.
Molecular basis of late infantile neuronal ceroid
lipofuscinosis. A, view from the top of the cartoon model in
Fig. 3D and rotated. The currently known pathogenic TPP1
missense mutations are mapped onto the TPP1 structure as labeled
spheres and are colored according to their impact on the TPP1
structure. Red colored spheres point to mutations compromising
the catalytic activity; blue colored spheres indicate
conformational destabilization, and gray colored spheres
designate unclear structural consequences. The Asn^286 residue
(turquoise) corresponds to one of the five N-glycosylation
sites. B, view of the catalytic cleft of the cartoon model in
Fig. 3D. TPP1 missense mutations are shown as stick models,
coloring scheme corresponds to A, except for mutations with
unclear effect that are colored in green.
|
|
|
|
|
|
The above figures are
reprinted
by permission from the ASBMB:
J Biol Chem
(2009,
284,
3976-3984)
copyright 2009.
|
|
|
|
|
|
|
