Group B Streptococcus alpha-like protein N-terminal domain

The Group B Streptococcus alpha-like protein N-terminal domain is a highly conserved N-terminal region of a family of surface proteins (including Alpha C, Rib, Alp1, Alp2, Alp3) present on Group B Streptococcus (GBS). This domain is structurally unique, consisting of a beta-sandwich and three-helix bundle, with similarities to type III fibronectin folds. It mediates GBS binding and internalization into human epithelial cells, acts as an invasin, and is key for virulence. The N-terminal domain contains motifs that bind to host integrins and heparin, supporting adhesion and translocation across epithelial barriers. Antibodies against these domains are highly immunogenic, block cell entry, and protect against infection, making this domain a promising candidate for GBS maternal vaccines to prevent neonatal disease[1][2][4][5].

Other names

Alp N-terminal domainAlpha C protein N-terminal domain (NtACP)GBS-NN (for the vaccine fusion protein containing representative N-terminal domains)Alpha-like protein family N-domain

Blockade by antibodies or soluble N-terminal domain fragments inhibits internalization and invasion of GBS into host epithelial cells[1][5] Antibodies mediate opsonophagocytic killing of GBS[5]