8HHJ

Crystal structure of the MafB2-CTMGI-2B16B6/MafI2MGI-2B16B6 complex

8HHJ の概要

• エントリーDOI: 10.2210/pdb8hhj/pdb
• 分子名称: MafB2 immunity protein, MafB2 toxin (3 entities in total)
• 機能のキーワード: polymorphic toxin system, mafb2, antimicrobial protein
• 由来する生物種: Neisseria meningitidis; 詳細
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 29718.67

構造登録者

Ha, S.C. (登録日: 2022-11-16, 公開日: 2023-11-15)

主引用文献

Park, S.H.,Jeong, S.J.,Ha, S.C.
Structural basis for the toxic activity of MafB2 from maf genomic island 2 (MGI-2) in N. meningitidis B16B6.
Sci Rep, 13:3365-3365, 2023

PubMed Abstract: The Maf polymorphic toxin system is involved in conflict between strains found in pathogenic Neisseria species such as Neisseria meningitidis and Neisseria gonorrhoeae. The genes encoding the Maf polymorphic toxin system are found in specific genomic islands called maf genomic islands (MGIs). In the MGIs, the MafB and MafI encode toxin and immunity proteins, respectively. Although the C-terminal region of MafB (MafB-CT) is specific for toxic activity, the underlying enzymatic activity that renders MafB-CT toxic is unknown in many MafB proteins due to lack of homology with domain of known function. Here we present the crystal structure of the MafB2-CT/MafI2 complex from N. meningitidis B16B6. MafB2-CT displays an RNase A fold similar to mouse RNase 1, although the sequence identity is only ~ 14.0%. MafB2-CT forms a 1:1 complex with MafI2 with a Kd value of ~ 40 nM. The complementary charge interaction of MafI2 with the substrate binding surface of MafB2-CT suggests that MafI2 inhibits MafB2-CT by blocking access of RNA to the catalytic site. An in vitro enzymatic assay showed that MafB2-CT has ribonuclease activity. Mutagenesis and cell toxicity assays demonstrated that His335, His402 and His409 are important for the toxic activity of MafB2-CT, suggesting that these residues are critical for its ribonuclease activity. These data provide structural and biochemical evidence that the origin of the toxic activity of MafB2 is the enzymatic activity degrading ribonucleotides.

PubMed: 36849501
DOI: 10.1038/s41598-023-30528-9

実験手法

X-RAY DIFFRACTION (1.5 Å)