Crystal structure of glutamate-1-semialdehyde-2,1-aminomutase from Arabidopsis thaliana.
Glutamate-1-semialdehyde-2,1-aminomutase (GSAM) catalyzes the isomerization of glutamate-1-semialdehyde (GSA) to 5-aminolevulinate (ALA) and is distributed in archaea, most bacteria and plants. Although structures of GSAM from archaea and bacteria have been resolved, a GSAM structure from a higher plant is not available, preventing further structure-function analysis. Here, the structure of GSAM from Arabidopsis thaliana (AtGSA1) obtained by X-ray crystallography is reported at 1.25 Å resolution. AtGSA1 forms an asymmetric dimer and displays asymmetry in cofactor binding as well as in the gating-loop orientation, which is consistent with previously reported Synechococcus GSAM structures. While one monomer binds PMP with the gating loop fixed in the open state, the other monomer binds either PMP or PLP and the gating loop is ready to close. The data also reveal the mobility of residues Gly163, Ser164 and Gly165, which are important for reorientation of the gating loop. Furthermore, the asymmetry of the AtGSA1 structure supports the previously proposed negative cooperativity between monomers of GSAM.
Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, People's Republic of China.
Yingxian
Y
Song
Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, People's Republic of China.
Hua
H
Pu
Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, People's Republic of China.
Tian
T
Jiang
Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, People's Republic of China.
Lixin
L
Zhang
Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, People's Republic of China.
Min
M
Ouyang
D017360:Arabidopsis / Q000201:enzymology*; D018360:Crystallography, X-Ray; D019751:Intramolecular Transferases / Q000737:chemistry*; D011487:Protein Conformation
D019751:Intramolecular Transferases; C061049:glutamate-1-semialdehyde 2,1-aminomutase
Arabidopsis thaliana; X-ray crystallography; asymmetry; gating loop; glutamate-1-semialdehyde-2,1-aminomutase; pyridoxal 5′-phosphate; pyridoxamine 5′-phosphate