Interleukin-1 beta (IL-1 beta)-converting enzyme cleaves the IL-1 beta precursor to mature IL-1 beta, an important mediator of inflammation. The identification of the enzyme as a unique cysteine protease and the design of potent peptide aldehyde inhibitors are described. Purification and cloning of the complementary DNA indicates that IL-1 beta-converting enzyme is composed of two nonidentical subunits that are derived from a single proenzyme, possibly by autoproteolysis. Selective inhibition of the enzyme in human blood monocytes blocks production of mature IL-1 beta, indicating that it is a potential therapeutic target.

Defects in the conversion of androstenedione to testosterone in the fetal testes by the enzyme 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) give rise to genetic males with female external genitalia. We have used expression cloning to isolate cDNAs encoding a microsomal 17 beta-HSD type 3 isozyme that shares 23% sequence identity with other 17 beta-HSD enzymes, uses NADPh as a cofactor, and is expressed predominantly in the testes. The 17 beta HSD3 gene on chromosome 9q22 contains 11 exons. Four substitution and two splice junction mutations were identified in the 17 beta HSD3 genes of five unrelated male pseudohermaphrodites. The substitution mutations severely compromised the activity of the 17 beta-HSD type 3 isozyme.

A survey of the human genome was performed to understand the constituency of protein methyltransferases (both protein arginine and lysine methyltransferases) and the relatedness of their catalytic domains. We identified 51 protein lysine methyltransferase proteins based on similarity to the canonical Drosophila Su(var)3-9, enhancer of zeste (E(z)), and trithorax (trx) domain. Disruptor of telomeric silencing-1-like, a known protein lysine methyltransferase, did not fit within the protein lysine methyltransferase family, but did group with the protein arginine methyltransferases, along with 44 other proteins, including the METTL and NOP2 ⁄ Sun domain family proteins. We show that a representative METTL, METTL11A, demonstrates catalytic activity as a histone methyltransferase. We also solved the co-crystal structures of disruptor of telomeric silencing-1-like with S-adenosylmethionine and S-adenosylhomocysteine bound in its active site. The conformation of both ligands is virtually identical to that found in known protein arginine methyltransferases, METTL and NOP2 ⁄ Sun domain family proteins and is distinct from that seen in the Drosophila Su(var)3-9, enhancer of zeste (E(z)), and trithorax (trx) domain protein lysine methyltransferases. We have developed biochemical assays for 11 members of the protein methyltransferase target class and have profiled the affinity of three ligands for these enzymes: the common methyl-donating substrate S-adenosylmethionine; the common reaction product S-adenosylhomocysteine; and the natural product sinefungin. The affinity of each of these ligands is mapped onto the family trees of the protein lysine methyltransferases and protein arginine methyltransferases to reveal patterns of ligand recognition by these enzymes.Key words: chemical biology, cheminformatics, drug discovery, enzyme structure, molecular recognition Abbreviations: DOT1L, disruptor of telomeric silencing-1-like; HGNC, HUGO Gene Nomenclature Committee; IPTG, isopropyl b-D-1-thiogalactopyranoside; NSUN, NOP2 ⁄ Sun domain family; PKMT, protein lysine methyltransferase; PMT, protein methyltransferase; PRDM, (PRDI-BF1 and RIZ homology) domain; PRMT, protein arginine methyltransferase; PSI-BLAST, position-specific iterated basic local alignment search tool; SAH, S-adenosylhomocysteine; SAM, S-adenosylmethionine; SETdomain, Drosophila Su(var)3-9, enhancer of zeste (E(z)), and trithorax (trx) domain.

No abstract