The structures of α_2u-globulin and its complex with a hyaline droplet inducer

Abstract

# 1999 International Union of Crystallography Printed in Denmark ± all rights reserved 2u -Globulin (A2U) is the major urinary protein excreted by adult male rats. The structure of a monoclinic crystal form of A2U was reported in 1992 [Bo È cskei et al. (1992). Nature (London), 360, 186±188]. The structures of an orthorhombic crystal form of A2U at 2.5 A Ê resolution (re®ned to an R factor of 0.248; R free = 0.264) and of a complex between A2U and d-limonene 1,2-epoxide (DLO) at 2.9 A Ê resolution (R factor = 0.248; R free = 0.260) are presented here. DLO is one of a diverse group of chemicals which cause a male rat-speci®c renal carcinogenesis called hyaline-droplet nephropathy. The rate-determining step in the development of this disorder is the binding of the toxin to A2U. Comparison of the cavities in A2U and in the corresponding mouse urinary protein (MUP) reveal that the former is tailor-made for small oval hydrophobic ligands such as DLO. The cavity in MUP is more shallow and elongated and cannot easily accommodate such ligands.

Structures of Two Major Allergens, Bla g 4 and Per a 4, from Cockroaches and Their IgE Binding Epitopes

“…A similar pattern of long-range disulfide is also observed in many non-allergenic lipocalins like insecticyanin from the tobacco hornworm (22), bilin-binding protein from the cabbage butterfly (23), and human apolipoprotein D (24). All previously identified lipocalin allergens like Mus m 1 (12), rat ␣ 2u -globulin (25), Equ c 1 (10), Fel d 4 (26), Bos d 2 (8), and Bos d 5 (9) contain single long-range disulfide bonds that connect the start of ␤D to the C terminus.…”

Crystal Structure of the Dog Lipocalin Allergen Can f 2: Implications for Cross-reactivity to the Cat Allergen Fel d 4

“…5). 41 Both MUP1 and A2U, with slightly more prominent and spherical hydrophobic cavities when compared to rCan f 2, act as pheromone carriers. 7,21 The relative conservation of specific aromatic and hydrophobic residues such as Phe38, Val40, Leu69, Leu82 and Tyr84 in rCan f 2 when compared to MUP1 and A2U indicates that similar molecules may bind to all three allergens (Fig.…”

Prediction of IgE-binding epitopes by means of allergen surface comparison and correlation to cross-reactivity

“…36 IgE-binding residues are known from the structure of bBLG in complex with a human IgE Fab. 5 With a surface-similarity excess threshold of 40% and a patch size threshold of 400 A 2 , we were able to detect 5 of the 15 binding residues on the bBLG surface (33% sensitivity) within a total number of 18 predicted residues in 2 individual surface patches.…”