The role of Zn2+ on the structure and stability of murine adenosine deaminase.

ABSTRACT: Adenosine deaminase (ADA) is a key enzyme in purine metabolism and crucial for normal immune competence. It is a 40 kDa monomeric TIM-barrel protein containing a tightly bound Zn(2+), which is required for activity. In this study, we have investigated the role of Zn(2+) with respect to ADA structure and stability. After removing Zn(2+), the crystallographic structure of the protein remains highly ordered and similar to that of the holo protein with structural changes limited to regions capping the active site pocket. The stability of the protein, however, is decreased significantly in the absence of Zn(2+). Denaturation with urea shows the midpoint to be about 3.5 M for the apo enzyme, compared with 6.4 M for the holo enzyme. ADA contains four tryptophan residues distant from the Zn(2+) si

SUBMITTER: Niu W 

PROVIDER: S-EPMC3005954 | biostudies-literature | 2010 Dec

REPOSITORIES: biostudies-literature