High-Resolution Crystal Structures of Δ⁵-3-Ketosteroid Isomerase with and without a Reaction Intermediate Analogue

Abstract

Equations 3b and 3c, which utilize abbreviations for terms in eq 3a, are correct as written. This error does not affect any of the data or conclusions in the paper.

Crystal Structure of γ-Hexachlorocyclohexane Dehydrochlorinase LinA from Sphingobium japonicum UT26

“…[22][23][24][25][26] Structural comparisons with homologous proteins A structural similarity search using DALI 27 revealed that the LinA protomer was similar to α + β barrel fold proteins, with various functions listed in Table 1. [22][23][24][25][26][28][29][30][31][32][33][34] LinA shows low amino acid sequence identities (16% at the highest) with these structurally similar proteins. The quaternary structures of the α + β barrel fold proteins are varied: dimeric, trimeric, tetrameric, and tetradecameric.…”

A Tale of Two Isomerases: Compact versus Extended Active Sites in Ketosteroid Isomerase and Phosphoglucose Isomerase

“…The overall structure of ppKSI M105A is similar to that of wild-type ppKSI. Superimposing the coordinates of wild-type ppKSI (PDB entry 1OH0) 21 and ppKSI M105A (this work) yields an rmsd of 0.5 Å over 123 α-carbon atoms (Figure 3). …”

Integron-associated Mobile Gene Cassettes Code for Folded Proteins: The Structure of Bal32a, a New Member of the Adaptable α+β Barrel Family

“…18 Like Bal32a, many aCb barrel fold proteins are dimeric, with the b-sheet forming the dimer interface. These close structural relatives of Bal32a include the enzymes ketosteroid isomerase (KSI), 19 nogalonic acid methyl ester cyclase (known as SnoaL) 20 and scytalone dehydratase (SD). 21 The overlay of Figure 2(d) emphasises the strong conservation across the family of bstrand elements forming the barrel scaffold, with most variations from Bal32a occurring at the top of the cone.…”

“…In all these cases, a conserved bulky residue (most commonly aromatic) forms the bottom of the cavity, e.g. Tyr14 in KSI, 19 Trp31 in SD. 21 Bal32a differs considerably from its structural homologs in this region, with the equivalent position being occupied by Gly31.…”

“…an Asn/Asp side-chain anchors the turn between helices A and B; a Gly Figure 4 where known) are generally varied in location across the sequences. In KSI, catalytic residues lie on helix A (Tyr14), strands S1 (Asp38) and S5 (Asp99), 19 yet in SnoaL, residues of C-terminal strands S5 (Gln105) and S6 (Asp121) are functional. 20 At one point on b-strand S6, however, a nucleophilic Asp residue is common to two members of the family, SnoaL (Asp121) and limonene-1,2-epoxide hydrolase (LEH) (Asp132).…”