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PDBsum entry 1psz
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Immune system
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PDB id
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1psz
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Contents |
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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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The crystal structure of pneumococcal surface antigen psaa reveals a metal-Binding site and a novel structure for a putative abc-Type binding protein.
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Authors
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M.C.Lawrence,
P.A.Pilling,
V.C.Epa,
A.M.Berry,
A.D.Ogunniyi,
J.C.Paton.
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Ref.
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Structure, 1998,
6,
1553-1561.
[DOI no: ]
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PubMed id
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Abstract
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Background:. The surface protein PsaA of the pathogenic bacterium Streptococcus
pneumoniae plays an essential role in its virulence. PsaA is a putative
ATP-binding cassette-type (ABC-type) binding protein involved in the uptake of
Mn2+ and possibly Zn2+ and is considered to be both a potential drug target and
and a candidate vaccine component. Results:. The structure of PsaA has been
determined to 2.0 A resolution using X-ray crystallography and is the first
structure obtained for an ABC-type binding protein from a Gram-positive
organism. The protein consists of two (beta/alpha)4 domains linked together by a
single helix. A metal-binding site is formed in the domain interface by the
sidechains of His67, His139, Glu205 and Asp280 and is occupied in the structure.
Conclusions:. The structural topology of PsaA is fundamentally different from
that of other ABC-type binding proteins determined thus far in that PsaA lacks
the characteristic 'hinge peptides' involved in conformational change upon
solute uptake and release. In our structure, the metal-binding site is probably
occupied by Zn2+. The site seems to be well conserved amongst related receptors
from both Gram-positive and Gram-negative bacteria.
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Figure 1.
Figure 1. The overall fold of PsaA. (a) View down the
twofold pseudosymmetry axis relating the domains. Within each
domain, b strands are shown in cyan and a helices in brown; the
domain-connecting helix is colored magenta. The connecting loops
within the N-terminal domain are in yellow, whilst those in the
C-terminal domain are colored green. The four metal-coordinating
residues are shown in ball-and-stick representation, with carbon
atoms colored gray, nitrogen atoms blue and oxygen atoms red.
The Zn2+ is shown in orange. (b) Stereogram of a Ca trace of
PsaA. The b strands are designated A-H and domain a helices a-h;
the location of the Zn2+ (orange) is also shown. The N and C
termini are shown as a blue and a red sphere, respectively, the
observed N terminus being Lys24. Every twentieth Ca atom is
highlighted as a black sphere and labeled. The view direction is
approximately orthogonal to that of (a). Figures were generated
using the programs MOLSCRIPT [39] and RASTER3D [40 and 41].
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The above figure is
reprinted
by permission from Cell Press:
Structure
(1998,
6,
1553-1561)
copyright 1998.
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Secondary reference #1
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Title
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Expression, Purification and preliminary x-Ray crystallographic analysis of psaa, A putative metal-Transporter protein of streptococcus pneumoniae.
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Authors
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P.A.Pilling,
M.C.Lawrence,
A.M.Berry,
A.D.Ogunniyi,
R.A.Lock,
J.C.Paton.
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Ref.
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Acta Crystallogr D Biol Crystallogr, 1998,
54,
1464-1466.
[DOI no: ]
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PubMed id
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Figure 1.
Figure 1 A single cluster of PsaA crystals grown according to
the seeding protocol described in the text. The typical size of
the larger crystals is 0.5 × 0.03 × 0.03 mm; the
variation in quality is readily apparent.
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The above figure is
reproduced from the cited reference
with permission from the IUCr
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