Novel structure of the N-terminal helical domain of BibA, a group B streptococcus immunogenic bacterial adhesin
Manne, Kartik ; Chattopadhyay, Debasish ; Agarwal, Vaibhav LU ; Blom, Anna M. LU
; Khare, Baldeep
; Chakravarthy, Srinivas
; Chang, Chungyu
; Ton-That, Hung
and Narayana, Sthanam V.L.
(2020)
In Acta crystallographica. Section D, Structural biology
76.
p.759-770
- Abstract
BibA, a group B streptococcus (GBS) surface protein, has been shown to protect the pathogen from phagocytic killing by sequestering a complement inhibitor: C4b-binding protein (C4BP). Here, the X-ray crystallographic structure of a GBS BibA fragment (BibA126-398) and a low-resolution small-angle X-ray scattering (SAXS) structure of the full-length N-terminal domain (BibA34-400) are described. The BibA126-398 fragment crystal structure displayed a novel and predominantly helical structure. The tertiary arrangement of helices forms four antiparallel three-helix-bundle-motif repeats, with one long helix from a bundle extending into the next. Multiple mutations on recombinant BibA34-400 delayed the degradation of the protein, and circular... (More)
BibA, a group B streptococcus (GBS) surface protein, has been shown to protect the pathogen from phagocytic killing by sequestering a complement inhibitor: C4b-binding protein (C4BP). Here, the X-ray crystallographic structure of a GBS BibA fragment (BibA126-398) and a low-resolution small-angle X-ray scattering (SAXS) structure of the full-length N-terminal domain (BibA34-400) are described. The BibA126-398 fragment crystal structure displayed a novel and predominantly helical structure. The tertiary arrangement of helices forms four antiparallel three-helix-bundle-motif repeats, with one long helix from a bundle extending into the next. Multiple mutations on recombinant BibA34-400 delayed the degradation of the protein, and circular dichroism spectroscopy of BibA34-400 suggested a similar secondary-structure composition to that observed in the crystallized BibA126-398 fragment. A model was generated for the 92 N-terminal residues (BibA34-125) using structural similarity prediction programs, and a BibA34-400 model was generated by combining the coordinates of BibA34-126 and BibA126-398. The X-ray structure of BibA126-398 and the model of BibA34-400 fitted well into the calculated SAXS envelope. One possible binding site for the BibA N-terminal domain was localized to the N-terminal CCP (complement-control protein) domains of the C4BP α-chain, as indicated by the decreased binding of BibA to a ΔCCP1 C4BP α-chain mutant. In summary, it is suggested that the GBS surface protein BibA, which consists of three antiparallel α-helical-bundle motifs, is unique and belongs to a new class of Gram-positive surface adhesins.
(Less)
- author
- Manne, Kartik
; Chattopadhyay, Debasish
; Agarwal, Vaibhav
LU
; Blom, Anna M.
LU
; Khare, Baldeep
; Chakravarthy, Srinivas
; Chang, Chungyu
; Ton-That, Hung
and Narayana, Sthanam V.L.
- organization
- publishing date
- 2020
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- BibA, C4b-binding proteins, group B streptococcus, immunogenic bacterial adhesins, three-helix-bundle-motif repeats
- in
- Acta crystallographica. Section D, Structural biology
- volume
- 76
- pages
- 12 pages
- publisher
- John Wiley and Sons
- external identifiers
-
- scopus:85088908979
- pmid:32744258
- ISSN
- 2059-7983
- DOI
- 10.1107/S2059798320008116
- language
- English
- LU publication?
- yes
- id
- 6ae81574-7cce-45c2-8461-fc4950250ced
- date added to LUP
- 2020-08-12 09:54:33
- date last changed
- 2021-04-13 03:58:16
@article{6ae81574-7cce-45c2-8461-fc4950250ced,
abstract = {<p>BibA, a group B streptococcus (GBS) surface protein, has been shown to protect the pathogen from phagocytic killing by sequestering a complement inhibitor: C4b-binding protein (C4BP). Here, the X-ray crystallographic structure of a GBS BibA fragment (BibA126-398) and a low-resolution small-angle X-ray scattering (SAXS) structure of the full-length N-terminal domain (BibA34-400) are described. The BibA126-398 fragment crystal structure displayed a novel and predominantly helical structure. The tertiary arrangement of helices forms four antiparallel three-helix-bundle-motif repeats, with one long helix from a bundle extending into the next. Multiple mutations on recombinant BibA34-400 delayed the degradation of the protein, and circular dichroism spectroscopy of BibA34-400 suggested a similar secondary-structure composition to that observed in the crystallized BibA126-398 fragment. A model was generated for the 92 N-terminal residues (BibA34-125) using structural similarity prediction programs, and a BibA34-400 model was generated by combining the coordinates of BibA34-126 and BibA126-398. The X-ray structure of BibA126-398 and the model of BibA34-400 fitted well into the calculated SAXS envelope. One possible binding site for the BibA N-terminal domain was localized to the N-terminal CCP (complement-control protein) domains of the C4BP α-chain, as indicated by the decreased binding of BibA to a ΔCCP1 C4BP α-chain mutant. In summary, it is suggested that the GBS surface protein BibA, which consists of three antiparallel α-helical-bundle motifs, is unique and belongs to a new class of Gram-positive surface adhesins.</p>},
author = {Manne, Kartik and Chattopadhyay, Debasish and Agarwal, Vaibhav and Blom, Anna M. and Khare, Baldeep and Chakravarthy, Srinivas and Chang, Chungyu and Ton-That, Hung and Narayana, Sthanam V.L.},
issn = {2059-7983},
language = {eng},
pages = {759--770},
publisher = {John Wiley and Sons},
series = {Acta crystallographica. Section D, Structural biology},
title = {Novel structure of the N-terminal helical domain of BibA, a group B streptococcus immunogenic bacterial adhesin},
url = {http://dx.doi.org/10.1107/S2059798320008116},
doi = {10.1107/S2059798320008116},
volume = {76},
year = {2020},
}