5Y2G

Structure of MBP tagged GBS CAMP

Summary for 5Y2G

• Entry DOI: 10.2210/pdb5y2g/pdb
• Related PRD ID: PRD_900001
• Descriptor: Maltose-binding periplasmic protein,Protein B, alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose, SULFATE ION (3 entities in total)
• Functional Keywords: camp factor, pore forming toxin, toxin
• Biological source: Escherichia coli; More
• Total number of polymer chains: 1
• Total formula weight: 66132.56

Authors

Jin, T.,Li, Y. (deposition date: 2017-07-25, release date: 2019-02-27, Last modification date: 2023-11-22)

Primary citation

Li, Y.,Zeng, W.,Li, Y.,Fan, W.,Ma, H.,Fan, X.,Jiang, J.,Brefo-Mensah, E.,Zhang, Y.,Yang, M.,Dong, Z.,Palmer, M.,Jin, T.
Structure determination of the CAMP factor of Streptococcus agalactiae with the aid of an MBP tag and insights into membrane-surface attachment.
Acta Crystallogr D Struct Biol, 75:772-781, 2019

PubMed Abstract: CAMP factor is a unique α-helical bacterial toxin that is known for its co-hemolytic activity in combination with staphylococcal sphingomyelinase. It was first discovered in the human pathogen Streptococcus agalactiae (also known as group B streptococcus), but homologous genes have been found in many other Gram-positive pathogens. In this study, the efforts that led to the determination of the first structure of a CAMP-family toxin are reported. Initially, it was possible to produce crystals of the native protein which diffracted to near 2.45 Å resolution. However, a series of technical obstacles were encountered on the way to structure determination. Over a period of more than five years, many methods, including selenomethionine labeling, mutations, crystallization chaperones and heavy-atom soaking, were attempted, but these attempts resulted in limited progress. The structure was finally solved using a combination of iodine soaking and molecular replacement using the crystallization chaperone maltose-binding protein (MBP) as a search model. Analysis of native and MBP-tagged CAMP-factor structures identified a conserved interaction interface in the C-terminal domain (CTD). The positively charged surface may be critical for binding to acidic ligands. Furthermore, mutations on the interaction interface at the CTD completely abolished its co-hemolytic activities. This study provides novel insights into the mechanism of the membrane-permeabilizing activity of CAMP factor.

PubMed: 31373576
DOI: 10.1107/S205979831901057X

Experimental method

X-RAY DIFFRACTION (3 Å)