Here is an example of how to shift the x-coordinates of all the geometries stored in the 'concord_roads.shp':
S1 = shaperead('concord_roads.shp');
S2 = S1;
for i=1:length(S2)
S2(i).X = S2(i).X +1e5; % replace appropriate shift here
end
figure(1); mapshow(S1);
figure(2); mapshow(S2);
You will notice that the x-coordinates in Figure 2 are all shifted by 1e5.
You may not need to apply this shift to all the geometries stored in the structure returned by shaperead so you may only need to apply this shift to a certain subset of the geometries describing the Pacific Ocean.
