Abstract: The present invention relates to the field of structural biology. More specifically, the present invention relates to novel antigen-binding chimeric proteins, their uses and methods in three-dimensional structural analysis of macromolecules, such as X-ray crystallography and high-resolution Cryo-EM, and their use as a therapeutic, diagnostic, or imaging tool. Even more specifically, the invention relates to a fusion of a scaffold protein and an antigen-binding domain wherein the scaffold protein of said fusion interrupts the Immunoglobulin domain topology to form a rigid chimer.

Abstract: The present invention relates to the field of bacterial Surface (S)-layer proteins, in particular to compounds capable of disrupting the bacterial S-Layer, specifically the S-Layer of Bacillus anthracis. More particularly, the invention provides for single domain antibodies for diagnosis and treatment of infection caused by pathogens with an S-Layer, in particular of Bacillus anthracis infection. The invention relates to S-Layer protein binding agents inhibiting bacterial growth and interrupting S-Layer assembly, useful in the treatment of bacterial infection, more specifically treatment of anthrax disease.