Crystal structure of a menaquinone biosynthetic enzyme, TthMqnD, complexed with its product, 1,4-dihydroxy-6-naphthoate

Introduction Recently, an alternative menaquinone (vitamin K2) biosynthetic pathway was found in some organisms [1]. Since human and their commensal intestinal bacteria, including lactobacilli, lack the alternative manaquinone biosynthetic pathway, this enzyme in pathogenic species, such as Helicobacter pylori and Campylobacter jejuni, is an attractive target for the development of chemotherapeutics. Here we report the structure of MqnD from Thermus thermophilus HB8 (TthMqnD: TTHA1568), an enzyme in the alternative menaquinone biosynthetic pathway, co-crystallized with its product, 1, 4-dihydroxy-6-naphtoate.