How can one determine the angle between the line of nodes and the major axis of the orbit of Mars?
The name for this angle is the Argument of Periapsis.
The Argument of Periapsis (or in this case, Perihelion, since Mars orbits the Sun) is the angle, in the plane of the orbit, measured in the direction of travel around the Orbit, from the Ascending Node, through the body being orbited, to the periapsis of the orbiting object.
Princeton's Planetary Systems page lists the Argument of Perihelion of Mars as $286.5°$ in 2006.
This would make the interior angle between the major axis of Mars and the line of nodes to be $360°-286.5° = 73.5°$, as of 2006.