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Interaction of Rv1625c, a mycobacterial class IIIa adenylyl cyclase, with a mammalian congener
Author(s) -
Guo Ying Lan,
Kurz Ursula,
Schultz Anita,
Linder Jürgen U.,
Dittrich Dorothea,
Keller Christine,
Ehlers Stefan,
Sander Peter,
Schultz Joachim E.
Publication year - 2005
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2005.04675.x
Subject(s) - adenylyl cyclase , biology , mycobacterium tuberculosis , transmembrane protein , recombinant dna , transmembrane domain , biochemistry , microbiology and biotechnology , membrane , enzyme , gene , tuberculosis , receptor , medicine , pathology
Summary The adenylyl cyclase Rv1625c from Mycobacterium tuberculosis codes for a protein with six transmembrane spans and a catalytic domain, i.e. it corresponds to one half of the pseudoheterodimeric mammalian adenylyl cyclases (ACs). Rv1625c is active as a homodimer. We investigated the role of the Rv1625c membrane domain and demonstrate that it efficiently dimerizes the protein resulting in a 7.5‐fold drop in K m for ATP. Next, we generated a duplicated Rv1625c AC dimer by a head‐to‐tail concatenation. This produced an AC with a domain order exactly as the mammalian pseudoheterodimers. It displayed positive cooperativity and a 60% increase of v max compared with the Rv1625c monomer. Further, we probed the compatibility of mycobacterial and mammalian membrane domains. The second membrane anchor in the Rv1625c concatamer was replaced with membrane domain I or II of rabbit type V AC. The mycobacterial and either mammalian membrane domains are compatible with each other and both recombinant proteins are active. A M. tuberculosis Rv1625c knockout strain was assayed in a mouse infection model. In vitro growth characteristics and in vivo organ infection and mortality were unaltered in the knockout strain indicating that AC Rv1625c alone is not a virulence factor.