You don't need protein. You need amino acids, which are the building blocks of protein.
The human metabolism can synthesize most of these, but we need 8 (so called essential) amino acids.
In the US a organization caalled "Agricultural Research Service" under the United States Department of Agriculture has published a online database of nutritional components of various foodstuffs. It is available at:
http://ndb.nal.usda.gov/ndb/nutrients/index
The essential amino acids are:
Phenylalanine
Valine
Threonine
Tryptophan
Methionine
Leucine
Isoleucine
Lysine
Histidine
Some of these were earlier considered to be non-essential, so different sources will publish slightly different lists. There are futhermore some other aminoacids which are essential for infants, namely cysteine, tyrosine and arginine.
(If using this information for important decisions, then please doublecheck with updated and official sources - it has been some years since I last read about the subject - they may have added added more amino-acids to the list of essentials)
When you run it all through the database referenced above you will basically be amazed of how little protein you actually need to stay healthy. This modern obsession with protein is - from a scientifically point of view - bordering quackery.
In the 1930-ies a Danish medial doctor, Mikkel Hindhede, actually conducted a series of clinical experiments to prove that it was possible to live a healthy life based on the foodstuffs available to the poorer segment of the population. In one of the experiments he actually had a test subject eating nothing but potatoes and strawberries for a number of weeks.
Edited to add: There is a article from an organization called "The Vegetarian Ressource Group", whose description of the subject is much better than mine. They have furthermore added a table showing the amino-acid components in various foodstuffs. The link is:
http://www.vrg.org/nutrition/protein.php
//Kim Horsevad