Abstract
Angiotensin II (Ang II) acts in the brain to increase blood pressure and is a major cause of cardiovascular disease and stroke. A novel non-AT1, non-AT2 binding site for ANG II in the brain was recently identified as a membrance bound-variant of the zinc metallopeptidase neurolysin. In the presence of PCMB (P-chloromercuribenzoate) and EDTA (Ethylenediaminetetracetate) 125I-sar1,ile8 Ang II binds with high affinity to neurolysin in rodent brain. To further explore the interaction of angiotensins with neurolysin we evaluated the 3-dimensional crystal structure of neurolysin. In addition we determined the importance of the zinc ion for angiotensin binding in the presence and absence of the zinc chelator EDTA. The zinc molecule is located at the active site of neurolysin and is required for catalytic activity. Results of the binding studies with 125I-sar1,ile8 Ang II in the presence of EDTA in rat brain and testis indicated that the zinc ion is not required for Ang II binding to neurolysin. Moreover, in the absence of EDTA the binding of 125sar1,ile8 ANg II was dramatically reduced in both tissues. Two possible explanations for these results are 1) That the presence of zinc in the active site of neurolysin inhibits Ang II binding to neurolysin or 2) That Ang II is rapidly metabolized by neurolysin in its active state and it dissociates from neurolysin rather than remaining bound as the intact peptide. Pharmacological targeting of brain neurolysin may have therapeutic value in treating cardiovascular disease and stroke.
Faculty Sponsors
Dr. Mark Jaffe, Dr. Robert C. Speth
Project Type
Event
Location
Alvin Sherman Library
Start Date
4-13-2012 1:00 PM
End Date
4-13-2012 5:30 PM
Assessing the Importance of the Chelator EDTA on Binding of an Angiotensin II Analog to Neurolysin in Rat Testis and Brain Tissue Utilizing 3-Dimensional Modeling and Radioligand Binding
Alvin Sherman Library
Angiotensin II (Ang II) acts in the brain to increase blood pressure and is a major cause of cardiovascular disease and stroke. A novel non-AT1, non-AT2 binding site for ANG II in the brain was recently identified as a membrance bound-variant of the zinc metallopeptidase neurolysin. In the presence of PCMB (P-chloromercuribenzoate) and EDTA (Ethylenediaminetetracetate) 125I-sar1,ile8 Ang II binds with high affinity to neurolysin in rodent brain. To further explore the interaction of angiotensins with neurolysin we evaluated the 3-dimensional crystal structure of neurolysin. In addition we determined the importance of the zinc ion for angiotensin binding in the presence and absence of the zinc chelator EDTA. The zinc molecule is located at the active site of neurolysin and is required for catalytic activity. Results of the binding studies with 125I-sar1,ile8 Ang II in the presence of EDTA in rat brain and testis indicated that the zinc ion is not required for Ang II binding to neurolysin. Moreover, in the absence of EDTA the binding of 125sar1,ile8 ANg II was dramatically reduced in both tissues. Two possible explanations for these results are 1) That the presence of zinc in the active site of neurolysin inhibits Ang II binding to neurolysin or 2) That Ang II is rapidly metabolized by neurolysin in its active state and it dissociates from neurolysin rather than remaining bound as the intact peptide. Pharmacological targeting of brain neurolysin may have therapeutic value in treating cardiovascular disease and stroke.
