Financial support: This study was supported in part by National Institutes of Health grant AI 17828. Jariyanart Gaywee received pre-doctoral support from the Royal Thai Army, Ministry of Defense, Thailand.
Gaywee J, Xu W-L, Radulovic S, Bessman MJ, Azad AF, 2002. The Rickettsia prowazekii invasion gene homolog (invA) encodes a nudix hydrolase active on adenosine (5′)-pentaphospho-(5′)-adenosine. Mol Cell Proteomics 1 :179–185.
Bochner BR, Lee PC, Wilson SW, Cutler CW, Ames BN, 1984. AppppA and related adenylated nucleotides are synthesized as a consequence of oxidative stress. Cell. 37 :225–232.
Guranowski A, 2000. Specific and nonspecific enzymes involved in the catabolism of mono- and dinucleoside polyphosphates. Pharmacol Ther 87 :117–139.
Mateo J, Miras-Portugal MT, Rotllan P, 1997. Ecto-enzymatic hydrolysis of diadenosine polyphosphates by cultured adrenomedullary vascular endothelial cells. Am J Physiol 273 :C918–C927.
Von Drygalski A, Ogilvie A, 2000. Ecto-diadenosine 5′,5′′′- P1,P4-tetraphosphate (Ap4A)-hydrolase is expressed as an ectoenzyme in a variety of mammalian cells and adds new aspects to the turnover of Ap4A. Biofactors 11 :179–187.
Aguilar JS, Reyes R, Asensio AC, Oakin S, Rotllan P, Miledi R, 2001. Ectoenzymatic breakdown of diadenosine polyphosphates by Xenopus laevis oocytes. Eur J Biochem 268 :1289–1297.
Feussner K, Guranowski A, Kostka S, Wasternack C, 1996. Diadenosine 5′,5′′′-P1,P4-tetraphosphate (Ap4A) hydrolase from tomato (Lycopersicon esculentum cv. Lukullus)—purification, biochemical properties and behaviour during stress. Zeitschr Naturforsch Section C J Biosci 51 :477–486.
Nielsen H, Engelbrecht J, Brunak S, Von Heijne G, 1997. Identification of prokaryotic and eukaryotic signal peptides and prediction of their cleavage sites. Protein Eng 10 :1–6.
Radulovic S, Feng HM, Morovic M, Djelalija B, Popov V, Crocquet-Valdes P, Walker DH, 1996. Isolation of Rickettsia akari from the patient in a region where Mediterranean spotted fever is endemic. Clin Infect Dis 22 :216–220.
Manor E, Carbonetti NH, Silverman DJ, 1994. Rickettsia rickettsii has proteins with cross-reacting epitopes to eukaryotic phospholipase A2 and phospholipase C. Microb Pathog 17 :99–109.
Authors’ addresses: Jariyanart Gaywee, Department of Microbiology, Armed Forces Research Institute of Medical Sciences, Bangkok 10400, Thailand. John B. Sacci, Jr, Suzana Radulovic, Magda S. Beier, and Abdu F. Azad, Department of Microbiology and Immunology, School of Medicine, University of Maryland, 655 West Baltimore Street, Baltimore, MD 21201.