Updated project metadata. We investigated herein the interaction between nucleolin (NCL) and a set of G4 sequences derived from the CEB25 human minisatellite which adopt a parallel topology while differing by the length of the central loop (from 9nt to1nt). It is revealed that NCL strongly binds to long-loop (9-5 nt) G4 whilst interacting weakly with the shorter variants (loop < 3nt). Photocrosslinking experiments using 5-bromouracil (BrdU) modified sequences further confirmed the loop-length dependency thereby indicating that the CEB25-WT (9nt) is the best G4 substrate. Quantitative proteomic analysis (LC-MS/MS) of the photocrosslinking product(s) obtained with NCL bound to this sequence enabled the identification of one contact site within the 9nt loop. The protein fragment identified is located in the helix of the RBD2 domain of NCL, shedding light on the role of this structural element in the G4-loop recognition. Then, the ability of a panel of benchmark G4 ligands to prevent the NCL/G4 interaction was explored. It was found that only the most potent ligand PhenDC3 is able to inhibit NCL binding, thereby suggesting that the terminal guanine quartet is also a strong determinant of G4 recognition, putatively through interaction with the RGG domain. This study puts forward the molecular mechanism by which NCL recognizes G4-containing long loops and leads to propose a model implying a concerted action of RBD2 and RGG domains to achieve specific G4 recognition via a dual loop-quartet interaction.