1SNM

ACTIVE SITE MUTANT GLU-43 (RIGHT ARROW) ASP IN STAPHYLOCOCCAL NUCLEASE DISPLAYS NONLOCAL STRUCTURAL CHANGES

Summary for 1SNM

• Entry DOI: 10.2210/pdb1snm/pdb
• Descriptor: THERMONUCLEASE PRECURSOR, CALCIUM ION, THYMIDINE-3',5'-DIPHOSPHATE, ... (4 entities in total)
• Functional Keywords: hydrolase (phosphoric diester)
• Biological source: Staphylococcus aureus
• Cellular location: Nuclease A: Secreted. Nuclease B: Membrane: P00644
• Total number of polymer chains: 1
• Total formula weight: 17271.57

Authors

Loll, P.J.,Lattman, E.E. (deposition date: 1990-02-15, release date: 1991-07-15, Last modification date: 2024-02-14)

Primary citation

Loll, P.J.,Lattman, E.E.
Active site mutant Glu-43 --> Asp in staphylococcal nuclease displays nonlocal structural changes.
Biochemistry, 29:6866-6873, 1990

PubMed Abstract: The crystal structure of the Glu-43----Asp mutant of staphylococcal nuclease complexed with Ca2+ and the inhibitor thymidine 3',5'-bisphosphate (pdTp) has been determined and refined by restrained least-squares methods to a conventional crystallographic R value of 0.174 at a resolution of 1.74 A. Throughout most of the structure, the conformation of the backbone atoms of the mutant is similar to that of the wild-type protein; however, the seemingly conservative mutation Glu----Asp has significantly perturbed the structure of a loop adjacent to the active site, as well as giving rise to looser binding of the essential calcium ion and to a less extensive network of bound water molecules in the active site. Crystal contacts that extend into the active site have also been altered by this amino acid substitution. The changes caused by this mutation are considerably more drastic than would have been predicted and should serve as caveats to those who would draw conclusions about structure-function relationships on the basis of site-directed mutagenesis experiments in the absence of structural data.

PubMed: 2397218
DOI: 10.1021/bi00481a016

Experimental method

X-RAY DIFFRACTION (1.74 Å)