Structural analysis of site-directed mutants of cellular retinoic acid-binding protein II addresses the relationship between structural integrity and ligand binding.
The structural integrity of cellular retinoic acid-binding protein II (CRABPII) has been investigated using the crystal structures of CRABPII mutants. The overall fold was well maintained by these CRABPII mutants, each of which carried multiple different mutations. A water-mediated network is found to be present across the large binding cavity, extending from Arg111 deep inside the cavity to the alpha2 helix at its entrance. This chain of interactions acts as a ;pillar' that maintains the integrity of the protein. The disruption of the water network upon loss of Arg111 leads to decreased structural integrity of the protein. A water-mediated network can be re-established by introducing the hydrophilic Glu121 inside the cavity, which results in a rigid protein with the alpha2 helix adopting an altered conformation compared with wild-type CRABPII.
Vaezeslami
Soheila
S
Rigaku Americas Corporation, 9009 New Trails Drive, The Woodlands, TX 77381, USA.
Jia
Xiaofei
X
Vasileiou
Chrysoula
C
Borhan
Babak
B
Geiger
James H
JH
D001120:Arginine / Q000737:chemistry; D001665:Binding Sites / Q000235:genetics; D003460:Crystallization; D015870:Gene Expression; D018698:Glutamic Acid / Q000737:chemistry; D006801:Humans; D008024:Ligands; D016297:Mutagenesis, Site-Directed; D050505:Mutant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D018168:Receptors, Retinoic Acid / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013329:Structure-Activity Relationship; D014867:Water
D008024:Ligands; D050505:Mutant Proteins; D018168:Receptors, Retinoic Acid; D011994:Recombinant Proteins; C082928:retinoic acid binding protein II, cellular; D014867:Water; D018698:Glutamic Acid; D001120:Arginine