Neisseria meningitidis isgram negativeobligate pathogen, and a common causative agent of bacterial meningitis and meningococcal diseases including meningococcemia, a life threatening sepsis. Fatty acid biosynthesis plays a vital role in all organisms including bacteria. Unlike higher organisms, bacteria use a type II fatty acid synthesis (FAS II) composed of a series of individual proteins, making FAS II enzymes excellent targets for antibiotics discovery. (3R)-hydroxymyristoyl-ACP dehydratase (NmfabZ) is an essential enzyme involved in  the FAS II pathway  and catalyzes the dehydration of beta-hydroxy fatty acids linked to an acyl carrier protein. Two key questions driving this research are the structural and functional elucidation of NmfabZ, and specifically, the enzymatic reactions and fatty acid chain specificity. To address these questions we solved the crystal structure of NmfabZ using X-ray data supported with small angel X-ray scattering data (SAXS) and performed a range of enzyme-substrate specificity assays. This study provides an enhanced understanding of these thioesterases, their role in N. meningitidis, and provides a platform for structure based design of inhibitors.