X-ray structure of ILL2, an auxin-conjugate amidohydrolase from Arabidopsis thaliana

被引:40
作者
Bitto, Eduard [2 ]
Bingman, Craig A. [2 ]
Bittova, Lenka [2 ]
Houston, Norma L. [3 ]
Boston, Rebecca S. [3 ]
Fox, Brian G. [1 ,2 ]
Phillips, George N., Jr. [1 ,2 ]
机构
[1] Univ Wisconsin, Dept Biochem, Madison, WI 53706 USA
[2] Univ Wisconsin, Ctr Eukaryot Struct Genom, Madison, WI 53706 USA
[3] N Carolina State Univ, Dept Plant Biol, Raleigh, NC 27695 USA
基金
美国国家科学基金会;
关键词
M20D peptidase family; auxin homeostasis; metalloenzyme; X-ray structure; ENDOPLASMIC-RETICULUM; CARBOXYPEPTIDASE-A; RETENTION SIGNAL; FAMILY; HYDROLASE; PROTEINS; SPECIFICITY; REFINEMENT; RESOURCE; SEQUENCE;
D O I
10.1002/prot.22124
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The plant hormone indole-3-acetic acid (IAA) is the most abundant natural auxin involved in many aspects of plant development and growth. The IAA levels in plants are modulated by a specific group of amidohydrolases from the peptidase M20D family that release the active hormone from its conjugated storage forms. Here, we describe the X-ray crystal structure of IAA-amino acid hydrolase IAA-leucine resistantlike gene 2 (ILL2) from Arabidopsis thaliana at 2.0 angstrom resolution. ILL2 preferentially hydrolyses the auxin-amino acid conjugate N(indol-3-acetyl)-alanine. The overall structure of ILL2 is reminiscent of dinuclear metallopeptidases from the M20 peptidase family. The structure consists of two domains, a larger catalytic domain with three-layer alpha beta alpha sandwich architecture and aminopeptidase topology and a smaller satellite domain with two-layer alpha beta-sandwich architecture and alpha-beta-plaits topology. The metal-coordinating residues in the active site of ILL2 include a conserved cysteine that clearly distinguishes this protein from previously structurally characterized members of the M20 peptidase family. Modeling of N-(indol-3-acetyl)-alanine into the active site of ILL2 suggests that Leu175 serves as a key determinant for the amino acid side-chain specificity of this enzyme. Furthermore, a hydrophobic pocket nearby the catalytic dimetal center likely recognizes the indolyl moiety of the substrate. Finally, the active site of ILL2 harbors an absolutely conserved glutamate (Glu172), which is well positioned to act as a general acid-base residue. Overall, the structure of ILL2 suggests that this enzyme likely uses a catalytic mechanism that follows the paradigm established for the other enzymes of the M20 peptidase family.
引用
收藏
页码:61 / 71
页数:11
相关论文
共 47 条
[1]   Extensive feature detection of N-terminal protein sorting signals [J].
Bannai, H ;
Tamada, Y ;
Maruyama, O ;
Nakai, K ;
Miyano, S .
BIOINFORMATICS, 2002, 18 (02) :298-305
[2]   ILR1, AN AMIDOHYDROLASE THAT RELEASES ACTIVE INDOLE-3-ACETIC-ACID FROM CONJUGATES [J].
BARTEL, B ;
FINK, GR .
SCIENCE, 1995, 268 (5218) :1745-1748
[3]   Inputs to the active indole-3-acetic acid pool:: De novo synthesis, conjugate hydrolysis, and indole-3-butyric acid β-oxidation [J].
Bartel, B ;
LeClere, S ;
Magidin, M ;
Zolman, BK .
JOURNAL OF PLANT GROWTH REGULATION, 2001, 20 (03) :198-216
[4]  
Bartel Bonnie, 1997, Annu Rev Plant Physiol Plant Mol Biol, V48, P51, DOI 10.1146/annurev.arplant.48.1.51
[5]   The Protein Data Bank [J].
Berman, HM ;
Westbrook, J ;
Feng, Z ;
Gilliland, G ;
Bhat, TN ;
Weissig, H ;
Shindyalov, IN ;
Bourne, PE .
NUCLEIC ACIDS RESEARCH, 2000, 28 (01) :235-242
[6]   A novel auxin conjugate hydrolase from wheat with substrate specificity for longer side-chain auxin amide conjugates [J].
Campanella, JJ ;
Olajide, AF ;
Magnus, V ;
Ludwig-Müller, J .
PLANT PHYSIOLOGY, 2004, 135 (04) :2230-2240
[7]   A molecular phylogenomic analysis of the ILRI-like family of IAA amidohydrolase genes [J].
Campanella, JJ ;
Larko, D ;
Smalley, J .
COMPARATIVE AND FUNCTIONAL GENOMICS, 2003, 4 (06) :584-600
[8]   His-404 and His-405 are essential for enzyme catalytic activities of a bacterial indole-3-acetyl-L-aspartic acid hydrolase [J].
Chou, JC ;
Welch, WH ;
Cohen, JD .
PLANT AND CELL PHYSIOLOGY, 2004, 45 (09) :1335-1341
[9]   CARBOXYPEPTIDASE-A [J].
CHRISTIANSON, DW ;
LIPSCOMB, WN .
ACCOUNTS OF CHEMICAL RESEARCH, 1989, 22 (02) :62-69
[10]   IAR3 encodes an auxin conjugate hydrolase from Arabidopsis [J].
Davies, RT ;
Goetz, DH ;
Lasswell, J ;
Anderson, MN ;
Bartel, B .
PLANT CELL, 1999, 11 (03) :365-376