Write a function drawCA(aname, coords) that uses the plot3 command to draw the C_α backbone of the protein. When calling this function, you should pass in the aname and coords variables returned by the readPDBfile function from Part 1. Your function for this part does not return anything; it draws a 3D plot.

Your drawCA function should loop over all the atoms, and pull out the xyz coordinates for all atoms with the name ' CA ', and ignore all the other atoms. The plot3() function is the 3D equivalent of the familiar plot(), and is called in much the same way. Try doc plot3 for more information.