4HAP

Crystal Structure of a GH7 family cellobiohydrolase from Limnoria quadripunctata in complex with cellobiose

Summary for 4HAP

• Entry DOI: 10.2210/pdb4hap/pdb
• Related: 4GWA 4HAQ
• Related PRD ID: PRD_900005
• Descriptor: GH7 family protein, beta-D-glucopyranose-(1-4)-beta-D-glucopyranose, CALCIUM ION, ... (5 entities in total)
• Functional Keywords: cellobiohydrolase, hydrolase
• Biological source: Limnoria quadripunctata
• Total number of polymer chains: 2
• Total formula weight: 94079.02

Authors

Martin, R.N.A.,McGeehan, J.E.,Streeter, S.D.,Cragg, S.M.,Guille, M.J.,Schnorr, K.M.,Kern, M.,Bruce, N.C.,McQueen-Mason, S.J. (deposition date: 2012-09-27, release date: 2013-06-12, Last modification date: 2024-10-30)

Primary citation

Kern, M.,McGeehan, J.E.,Streeter, S.D.,Martin, R.N.,Besser, K.,Elias, L.,Eborall, W.,Malyon, G.P.,Payne, C.M.,Himmel, M.E.,Schnorr, K.,Beckham, G.T.,Cragg, S.M.,Bruce, N.C.,McQueen-Mason, S.J.
Structural characterization of a unique marine animal family 7 cellobiohydrolase suggests a mechanism of cellulase salt tolerance
Proc.Natl.Acad.Sci.USA, 110:10189-10194, 2013

PubMed Abstract: Nature uses a diversity of glycoside hydrolase (GH) enzymes to convert polysaccharides to sugars. As lignocellulosic biomass deconstruction for biofuel production remains costly, natural GH diversity offers a starting point for developing industrial enzymes, and fungal GH family 7 (GH7) cellobiohydrolases, in particular, provide significant hydrolytic potential in industrial mixtures. Recently, GH7 enzymes have been found in other kingdoms of life besides fungi, including in animals and protists. Here, we describe the in vivo spatial expression distribution, properties, and structure of a unique endogenous GH7 cellulase from an animal, the marine wood borer Limnoria quadripunctata (LqCel7B). RT-quantitative PCR and Western blot studies show that LqCel7B is expressed in the hepatopancreas and secreted into the gut for wood degradation. We produced recombinant LqCel7B, with which we demonstrate that LqCel7B is a cellobiohydrolase and obtained four high-resolution crystal structures. Based on a crystallographic and computational comparison of LqCel7B to the well-characterized Hypocrea jecorina GH7 cellobiohydrolase, LqCel7B exhibits an extended substrate-binding motif at the tunnel entrance, which may aid in substrate acquisition and processivity. Interestingly, LqCel7B exhibits striking surface charges relative to fungal GH7 enzymes, which likely results from evolution in marine environments. We demonstrate that LqCel7B stability and activity remain unchanged, or increase at high salt concentration, and that the L. quadripunctata GH mixture generally contains cellulolytic enzymes with highly acidic surface charge compared with enzymes derived from terrestrial microbes. Overall, this study suggests that marine cellulases offer significant potential for utilization in high-solids industrial biomass conversion processes.

PubMed: 23733951
DOI: 10.1073/pnas.1301502110

Experimental method

X-RAY DIFFRACTION (1.6 Å)