It would be a little difficult to measure the amount of protein present in one specific fruit. However, for the purpose of answering this question, we can use the information of the amount of protein found on fruits per 100 grams.
These are the following fruits from largest to smallest: Guavas contain 2.6 grams of protein per 100 grams, passion fruit has 2.2 grams of protein, mulberries and avocados both have 2 grams of protein, kumquats have 1.9, pomegranate and jackfruit both have 1.7 grams, blackberries, apricot and currants have 1.4 grams, raspberries and kiwi have 1.2 grams, nectarines, cherries and bananas have 1.1 grams, starfruit and oranges both have 1 gram of protein, grapefruit and peaches both have 0.9, cantaloupe has 0.8, strawberries have 0.7, watermelon has 0.6 and honeydew lemon has 0.5.