PDBsum entry 2jk3

Transcription

PDB id: 2jk3

Contents

Protein chains

182 a.a. *

Ligands

SO4

Waters ×140

* Residue conservation analysis

PDB id:

2jk3

Name:

Transcription

Title:

Crystal structure of the hlyiir mutant protein with residues 169-186 substituted by gssgssg linker

Structure:

Hemolysin ii regulatory protein. Chain: a, b. Fragment: residues 4-168,187-201. Engineered: yes. Other_details: segment 169-186 substituted by gssgssg linker

Source:

Bacillus cereus. Organism_taxid: 1396. Strain: b771. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.20Å R-factor: 0.201 R-free: 0.254

Authors:

O.V.Kovalevskiy,A.S.Solonin,A.A.Antson

Key ref:

O.V.Kovalevskiy et al. (2010). Structural investigation of transcriptional regulator HlyIIR: influence of a disordered region on protein fold and dimerization. Proteins, 78, 1870-1877. PubMed id: 20225260

Date:

11-Aug-08 Release date: 19-Aug-08

Protein chains

Q7X506  (Q7X506_BACCE) -  Hemolysin II regulatory protein from Bacillus cereus

Seq: 201 a.a.

Struc: 182 a.a.*

* PDB and UniProt seqs differ at 2 residue positions (black crosses)

Proteins 78:1870-1877 (2010)

PubMed id: 20225260

Structural investigation of transcriptional regulator HlyIIR: influence of a disordered region on protein fold and dimerization.

O.V.Kovalevskiy, A.S.Solonin, A.A.Antson.

ABSTRACT

B. cereus HlyIIR belongs to the TetR family of dimeric transcriptional regulators. Unlike other members of the TetR family, HlyIIR contains an insert between alpha-helices alpha8 and alpha9, which is located at the subunit-subunit interface. N-terminal segment of this insert (amino acids, Pro161-Ser169) forms a short alpha-helix alpha8* that occupies a complementary cavity on the surface of the adjacent subunit, whereas the C-terminal segment comprising 16 amino acids (Leu170-Glu185) is disordered. To understand whether this disordered segment is important for protein's function, we determined crystal structures of two engineered HlyIIR proteins where this segment was either substituted by a seven-residue flexible Ser-Gly linker or replaced by a cleavable peptide containing proteolytic sites at both ends. Unexpectedly, alteration or proteolytic removal of the disordered segment resulted in changes in protein's conformation and in a remarkable rearrangement at the subunit-subunit interface. X-ray structures of the two engineered proteins revealed an unusual plasticity at the dimerization interface of HlyIIR enabling it to form dimers stabilized by different sets of interactions. Structural comparison indicates that in spite of the flexible nature of the disordered segment, it is critical for maintaining the native structure as it influences the position of alpha8*. The data demonstrate how disordered loops on protein surfaces may affect folding and subunit-subunit interactions.