1AXK

ENGINEERED BACILLUS BIFUNCTIONAL ENZYME GLUXYN-1

Summary for 1AXK

• Entry DOI: 10.2210/pdb1axk/pdb
• Descriptor: GLUXYN-1, CALCIUM ION (3 entities in total)
• Functional Keywords: gluxyn-1, bifunctional, fusion protein, 1, 4-beta-xylanase, 3-1, 4-beta-glucanase, hybrid enzyme
• Biological source: Bacillus subtilis
• Total number of polymer chains: 2
• Total formula weight: 87705.51

Authors

Ay, J.,Heinemann, U. (deposition date: 1997-10-16, release date: 1999-05-11, Last modification date: 2024-10-30)

Primary citation

Ay, J.,Gotz, F.,Borriss, R.,Heinemann, U.
Structure and function of the Bacillus hybrid enzyme GluXyn-1: native-like jellyroll fold preserved after insertion of autonomous globular domain.
Proc.Natl.Acad.Sci.USA, 95:6613-6618, 1998

PubMed Abstract: The 1,3-1,4-beta-glucanase from Bacillus macerans (wtGLU) and the 1, 4-beta-xylanase from Bacillus subtilis (wtXYN) are both single-domain jellyroll proteins catalyzing similar enzymatic reactions. In the fusion protein GluXyn-1, the two proteins are joined by insertion of the entire XYN domain into a surface loop of cpMAC-57, a circularly permuted variant of wtGLU. GluXyn-1 was generated by protein engineering methods, produced in Escherichia coli and shown to fold spontaneously and have both enzymatic activities at wild-type level. The crystal structure of GluXyn-1 was determined at 2.1 A resolution and refined to R = 17.7% and R(free) = 22.4%. It shows nearly ideal, native-like folding of both protein domains and a small, but significant hinge bending between the domains. The active sites are independent and accessible explaining the observed enzymatic activity. Because in GluXyn-1 the complete XYN domain is inserted into the compact folding unit of GLU, the wild-type-like activity and tertiary structure of the latter proves that the folding process of GLU does not depend on intramolecular interactions that are short-ranged in the sequence. Insertion fusions of the GluXyn-1 type may prove to be an easy route toward more stable bifunctional proteins in which the two parts are more closely associated than in linear end-to-end protein fusions.

PubMed: 9618460
DOI: 10.1073/pnas.95.12.6613

Experimental method

X-RAY DIFFRACTION (2.1 Å)