Geldanamycin induces the degradation of proteins that are mutated or overexpressed in tumor cells such as v-Src, Bcr-Abl, p53, and ERBB2. This effect is mediated via HSP90. Despite its potent antitumor potential, geldanamycin presents several major drawbacks as a drug candidate such as hepatotoxicity, further, Jilani et al.. reported that geldanamycin induces the apoptosis of erythrocytes under physiological concentrations.[4] These side effects have led to the development of geldanamycin analogues, in particular analogues containing a derivatisation at the 17 position:
Geldanamycin was originally discovered in the organism Streptomyces hygroscopicus.[5] It is a macrocyclic polyketide that is synthesized by a Type I polyketide synthase. The genes gelA, gelB, and gelC encode for the polyketide synthase. The PKS is first loaded with 3-amino-5-hydroxybenzoic acid (AHBA). It then utilizes malonyl-CoA, methylmalonyl-CoA, and methoxymalonyl-CoA to synthesize the precursor molecule Progeldanamycin.[6] This precursor is subjected to several enzymatic and non-enzymatic tailoring steps to produce the active molecule geldanamycin, which include hydroxylation, O-methylation, carbamoylation, and oxidation.[7]
^He, W.; Wu, L.; Gao, Q.; Du, Y.; Wang, Y. (2006). "Identification of AHBA Biosynthetic Genes Related to Geldanamycin Biosynthesis in Streptomyces hygroscopicus 17997". Current Microbiology. 52 (3): 197–203. doi:10.1007/s00284-005-0203-y. PMID16502293. S2CID22291736.
^Kim, W.; Lee, D.; Hong, S. S.; Na, Z.; Shin, J. C.; Roh, S. H.; Wu, C. Z.; Choi, O.; Lee, K.; Shen, Y. M.; Paik, S. G.; Lee, J. J.; Hong, Y. S. (2009). "Rational Biosynthetic Engineering for Optimization of Geldanamycin Analogues". ChemBioChem. 10 (7): 1243–1251. doi:10.1002/cbic.200800763. PMID19308924. S2CID3273370.
^Lee, D.; Lee, K.; Cai, X. F.; Dat, N. T.; Boovanahalli, S. K.; Lee, M.; Shin, J. C.; Kim, W.; Jeong, J. K.; Lee, J. S.; Lee, C. H.; Lee, J. H.; Hong, Y. S.; Lee, J. J. (2006). "Biosynthesis of the Heat-Shock Protein 90 Inhibitor Geldanamycin: New Insight into the Formation of the Benzoquinone Moiety". ChemBioChem. 7 (2): 246–248. doi:10.1002/cbic.200500441. PMID16381049. S2CID42998903.