The present invention relates to novel protein pores and their uses in analyte detection and characterisation. The invention particularly relates to an isolated pore complex formed by a CsgG-like pore and a modified CsgF peptide, or a homologue or mutant thereof, thereby incorporating an additional channel constriction or reader head in the nanopore. The invention further relates to a transmembrane pore complex and methods for production of the pore complex and for use in molecular sensing and nucleic acid sequencing applications.