4RMB

Crystal structure of keratin 4 binding domain of surface adhesin Srr-1 of S.agalactiae

Summary for 4RMB

• Entry DOI: 10.2210/pdb4rmb/pdb
• Related: 4mbo
• Descriptor: Serine rich repeat protein-1 (Srr-1) (2 entities in total)
• Functional Keywords: variant of dev-igg fold, adhesin, keratin 4, bacterial cell surface, beta sheet complementation, cell adhesion
• Biological source: Streptococcus agalactiae NEM316
• Cellular location: Secreted, cell wall ; Peptidoglycan-anchor : Q8E473
• Total number of polymer chains: 2
• Total formula weight: 37052.52

Authors

Ponnuraj, K.,Sundaresan, R. (deposition date: 2014-10-21, release date: 2015-02-11, Last modification date: 2023-09-20)

Primary citation

Sundaresan, R.,Samen, U.,Ponnuraj, K.
Structure of KRT4 binding domain of Srr-1 from Streptococcus agalactiae reveals a novel beta-sheet complementation.
Int.J.Biol.Macromol., 75C:97-105, 2015

PubMed Abstract: The serine rich repeat protein-1 (Srr-1) is an adhesive protein of Streptococcus agalactiae. It is the first bacterial protein identified to interact with human keratin 4 (K4 or KRT4). Within Srr-1, the residues 311-641 constitute the non-repeat ligand binding region (Srr-1-BR(311-641)). The C-terminal part of Srr-1-BR(311-641), comprising of residues 485-642 (termed Srr-1-K4BD), have been identified to bind to K4. Here we report the crystal structure of recombinant Srr-1-K4BD(485-642) and its possible mode of interaction with K4 through docking studies. The dimeric structure of Srr-1-K4BD(485-642) reveals a novel two way "slide lock" parallel β-sheet complementation where the C-terminal strand of one monomer is positioned anti-parallel to the N-terminal strand of the adjacent monomer and this arrangement is not seen so far in any of the homologous structures. The dimerization of Srr-1-K4BD(485-642) observed both in the crystal structure and in solution suggests that similar domain association could also be possible in in vivo and we propose this association would likely generate a new binding site for another host molecule. It is likely that the adhesin can recognize multiple ligands using its ligand binding sub-domains through their intra and inter domain association with one another.

PubMed: 25603146
DOI: 10.1016/j.ijbiomac.2014.12.048

Experimental method

X-RAY DIFFRACTION (1.7 Å)