Ka Bian and Ferid Murad

Department of Integrative Biology and Pharmacology, The Institute of Molecular Medicine, The University of Texas-Houston Medical School, 6431 Fannin, Houston, TX 77030

FIGURES

Figure 1. Functional structure of NOS homodimmer.

Figure 2. The NOS-catalysed nitric oxide formation.

Figure 3. Biological pathways for NO2-Tyr formation.

Figure 4. Trichenelle spiralis infection -induced elevation of MPO. Irradiation (open circle) shows the inhibition of MPO expression.

Figure 5. Trichenelle spiralis infection can set into motion systemic mechanism(s) that down regulate NOS-2 expression in both jejunum and ileum.

Figure 6. NOS-2 deficiency failed to affect T. spiralis infection (MPO)-induced protein tyrosine nitration. 5 distinct bands of NO2-Tyr were detected in the jejunum tissue after 7 days of parasite infection (T.S.). Comparing with the control (CF-1) mice, the comparable significant levels of tyrosine nitration can be found in NOS-2 KO mice. Detected NO2-Tyr bands were confirmed by anti-NO2-Tyr antibody that was pre-absorbed with free L-NO2-Tyr. Each indicated lane number represents an individual animal used in the experiment.

Figure 7. Role ofprotein tyrosine nitration in smooth muscle contractility.

Figure 8. Effect of MPO on Ca²⁺ channel protein nitration and smooth muscle contraction. Left panel: Homogenates of 10 days T. spiralis-infected jejunum were immunoprecipitated with anti-NO2-Tyr and anti-Ca²⁺ -channel a1C antibodies. The precipitates then were cross treated with anti-Ca²⁺-channel a1C and NO2-Tyr antibodies using Western blotting techniques. Results from both experiments indicated that the L-type Ca²⁺-channel protein was nitrated during inflammation. Right panel: The strips of longitudinal muscle were removed from jejunum and placed in tissue baths and isometric contractions were recorded. Treatment of a muscle strip with 50 nM MPO for 60 mins resulted in a marked delay in the onset and a decrease in the velocity of the phasic phase of a carbachol-induced contraction. The potassium-induced contraction also was markedly inhibited.

Figure 9. Result of Western blot with anti-NO2-Tyr antibody shows tyrosine residue in BSA could be nitrated under the condition of heme-NO₂-H₂O₂ treatment system.