3IH9

Crystal Structure Analysis of Mglu in its tris form

Summary for 3IH9

• Entry DOI: 10.2210/pdb3ih9/pdb
• Related: 3IF5 3IH8 3IHA 3IHB
• Descriptor: Salt-tolerant glutaminase (2 entities in total)
• Functional Keywords: salt-tolerant glutaminase, hydrolase
• Biological source: Micrococcus luteus (Micrococcus lysodeikticus)
• Total number of polymer chains: 2
• Total formula weight: 96607.03

Authors

Yoshimune, K.,Shirakihara, Y. (deposition date: 2009-07-29, release date: 2010-01-19, Last modification date: 2023-11-01)

Primary citation

Yoshimune, K.,Shirakihara, Y.,Wakayama, M.,Yumoto, I.
Crystal structure of salt-tolerant glutaminase from Micrococcus luteus K-3 in the presence and absence of its product l-glutamate and its activator Tris
Febs J., 277:738-748, 2010

PubMed Abstract: Glutaminase from Micrococcus luteus K-3 [Micrococcus glutaminase (Mglu); 456 amino acid residues (aa); 48 kDa] is a salt-tolerant enzyme. Our previous study determined the structure of its major 42-kDa fragment. Here, using new crystallization conditions, we determined the structures of the intact enzyme in the presence and absence of its product L-glutamate and its activator Tris, which activates the enzyme by sixfold. With the exception of a 'lid' part (26-29 aa) and a few other short stretches, the structures were all very similar over the entire polypeptide chain. However, the presence of the ligands significantly reduced the length of the disordered regions: 41 aa in the unliganded structure (N), 21 aa for L-glutamate (G), 8 aa for Tris (T) and 6 aa for both L-glutamate and Tris (TG). L-glutamate was identified in both the G and TG structures, whereas Tris was only identified in the TG structure. Comparison of the glutamate-binding site between Mglu and salt-labile glutaminase (YbgJ) from Bacillus subtilis showed significantly smaller structural changes of the protein part in Mglu. A comparison of the substrate-binding pocket of Mglu, which is highly specific for L-glutamine, with that of Erwinia carotovora asparaginase, which has substrates other than L-glutamine, shows that Mglu has a larger substrate-binding pocket that prevents the binding of L-asparagine with proper interactions.

PubMed: 20050917
DOI: 10.1111/j.1742-4658.2009.07523.x

Experimental method

X-RAY DIFFRACTION (2.5 Å)