3VTR
Crystal Structure of insect beta-N-acetyl-D-hexosaminidase OfHex1 E328A complexed with TMG-chitotriomycin
Summary for 3VTR
| Entry DOI | 10.2210/pdb3vtr/pdb |
| Related | 3NSM 3NSN |
| Related PRD ID | PRD_900080 |
| Descriptor | N-acetylglucosaminidase, 2-deoxy-2-(trimethylammonio)-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, 2-acetamido-2-deoxy-beta-D-glucopyranose, ... (4 entities in total) |
| Functional Keywords | insect, chitin, beta-n-acetyl-d-hexosaminidase, tmg-chitotriomycin, hydrolase-antibiotic complex, hydrolase/antibiotic |
| Biological source | Ostrinia furnacalis (Asian corn borer) |
| Total number of polymer chains | 1 |
| Total formula weight | 66769.07 |
| Authors | |
| Primary citation | Liu, T.,Zhou, Y.,Chen, L.,Chen, W.,Liu, L.,Shen, X.,Zhang, W.,Zhang, J.,Yang, Q. Structural insights into cellulolytic and chitinolytic enzymes revealing crucial residues of insect beta-N-acetyl-D-hexosaminidase Plos One, 7:e52225-e52225, 2012 Cited by PubMed Abstract: The chemical similarity of cellulose and chitin supports the idea that their corresponding hydrolytic enzymes would bind β-1,4-linked glucose residues in a similar manner. A structural and mutational analysis was performed for the plant cellulolytic enzyme BGlu1 from Oryza sativa and the insect chitinolytic enzyme OfHex1 from Ostrinia furnacalis. Although BGlu1 shows little amino-acid sequence or topological similarity with OfHex1, three residues (Trp(490), Glu(328), Val(327) in OfHex1, and Trp(358), Tyr(131) and Ile(179) in BGlu1) were identified as being conserved in the +1 sugar binding site. OfHex1 Glu(328) together with Trp(490) was confirmed to be necessary for substrate binding. The mutant E328A exhibited a 8-fold increment in K(m) for (GlcNAc)(2) and a 42-fold increment in K(i) for TMG-chitotriomycin. A crystal structure of E328A in complex with TMG-chitotriomycin was resolved at 2.5 Å, revealing the obvious conformational changes of the catalytic residues (Glu(368) and Asp(367)) and the absence of the hydrogen bond between E328A and the C3-OH of the +1 sugar. V327G exhibited the same activity as the wild-type, but acquired the ability to efficiently hydrolyse β-1,2-linked GlcNAc in contrast to the wild-type. Thus, Glu(328) and Val(327) were identified as important for substrate-binding and as glycosidic-bond determinants. A structure-based sequence alignment confirmed the spatial conservation of these three residues in most plant cellulolytic, insect and bacterial chitinolytic enzymes. PubMed: 23300622DOI: 10.1371/journal.pone.0052225 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.5 Å) |
Structure validation
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