title: 4-oxatetradecanoic acid is fungicidal for Cryptococcus neoformans and inhibits replication of human immunodeficiency virus I.
abstract: Candida albicans and Cryptococcus neoformans are major causes of systemic fungal infections, particularly in patients with acquired immunodeficiency syndrome. Metabolic labeling studies revealed that these organisms synthesize a small number of N-myristoylproteins, the most prominent being 20-kDa ADP-ribosylation factors (Arfs). C. albicans Arf has approximately 80% identity with the essential Arf1 and Arf2 proteins of Saccharomyces cerevisiae. [3H]Myristic acid analogs with oxygen for -CH2- substitutions at C4, C6, C11, and C13 are incorporated into cellular N-myristoylproteins, phospholipids, and neutral lipids produced by these three yeasts during exponential growth at 30 degrees C in complex media. Analog- and organism-specific differences in the efficiency of labeling of proteins and lipid classes were observed. The effects of oxatetradecanoic acids with oxygen for -CH2- substitutions at C3-C13 on C. neoformans, C. albicans, and S. cerevisiae were assessed during mid-log phase growth at 30 degrees C. A single dose of 3-oxa-, 4-oxa-, 5-oxa- or 6-oxatetradecanoic acid (O3-O6, final concentration = 300 microM) was able to inhibit growth of C. neoformans in the order O4 greater than O5 greater than O3 approximately O6. The other compounds were inactive. 4-Oxatetradecanoic acid was fungicidal, producing a 10,000-fold reduction in viable cell number 1 h after administration and continued suppression of cell growth for 7 h. A clear dose response was observed over a concentration range of 100-300 microM. 4-Oxatridecanoic acid was 100-fold less potent in reducing cell viability than 4-oxatetradecanoic acid but more potent than 5-oxatridecanoic acid. O4 produced approximately 10-100-fold reductions in the viability of C. albicans and S. cerevisiae at 300-500 microM, respectively, whereas O5 and O6 were less active. Since N-myristoylation of the Pr55gag polyprotein precursor produced by human immunodeficiency virus I (HIV-I) is essential for its assembly, we also assessed the antiviral effects of 4-oxatetradecanoic acid. O4 is able to produce a 50% reduction in the replication of HIV-I in acutely infected human T-lymphocyte cell lines at a concentration of 18 microM. Together, these data suggest that (i) the position of the oxygen for methylene substitution is a critical determinant of the fungicidal activity of O4 and (ii) NMT may be an attractive therapeutic target for treating opportunistic fungal infections in patients infected with HIV-I.
authors.affiliation: Department of Molecular Biology and Pharmacology, Washington University School of Medicine, St. Louis, Missouri 63110.
authors.forename: C A
authors.initials: CA
authors.lastname: Langner
authors.forename: J K
authors.initials: JK
authors.lastname: Lodge
authors.forename: S J
authors.initials: SJ
authors.lastname: Travis
authors.forename: J E
authors.initials: JE
authors.lastname: Caldwell
authors.forename: T
authors.initials: T
authors.lastname: Lu
authors.forename: Q
authors.initials: Q
authors.lastname: Li
authors.forename: M L
authors.initials: ML
authors.lastname: Bryant
authors.forename: B
authors.initials: B
authors.lastname: Devadas
authors.forename: G W
authors.initials: GW
authors.lastname: Gokel
authors.forename: G S
authors.initials: GS
authors.lastname: Kobayashi
mesh_terms: D020823:ADP-Ribosylation Factor 1; D020727:ADP-Ribosylation Factors; D000595:Amino Acid Sequence; D000935:Antifungal Agents; D000998:Antiviral Agents / Q000494:pharmacology*; D001483:Base Sequence; D002176:Candida albicans / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D002352:Carrier Proteins / Q000378:metabolism; D003455:Cryptococcus neoformans / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D005230:Fatty Acids, Nonesterified / Q000378:metabolism / Q000494:pharmacology*; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015497:HIV-1 / Q000187:drug effects* / Q000502:physiology; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D009227:Myristic Acids / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid; D013329:Structure-Activity Relationship; D014779:Virus Replication / Q000187:drug effects*
chemical_list: D000935:Antifungal Agents; D000998:Antiviral Agents; D002352:Carrier Proteins; D005230:Fatty Acids, Nonesterified; D009227:Myristic Acids; C076272:4-oxatetradecanoic acid; D019204:GTP-Binding Proteins; D020823:ADP-Ribosylation Factor 1; D020727:ADP-Ribosylation Factors