This is the extracellular domain 1 (MapZextra1) found in Streptococcus pneumoniae cell division site positioning protein MapZ. MapZ ensures accurate placement of the bacterial division site. The domain is a rigid four alpha-helices with two flexible linkers. The N-terminal end of MapZextra1 is connected to the trans-membrane segment of MapZ whilst the C-terminal is linked to MapZextra2 via a serine rich linker (SRL).The highly conserved residues are not accessible at the surface but are directly involved in many inter-helices interactions allowing for rigidity [1].

1: Structure-function analysis of the extracellular domain of the pneumococcal cell\tdivision site positioning protein MapZ. Manuse S, Jean NL, Guinot M, Lavergne JP, Laguri C, Bougault CM, VanNieuwenhze MS, Grangeasse C, Simorre JP; Nat Commun. 2016;7:12071. PMID:27346279